An I/O controller for virtual pinball machines: accelerometer nudge sensing, analog plunger input, button input encoding, LedWiz compatible output controls, and more.

Dependencies:   mbed FastIO FastPWM USBDevice

Fork of Pinscape_Controller by Mike R

/media/uploads/mjr/pinscape_no_background_small_L7Miwr6.jpg

This is Version 2 of the Pinscape Controller, an I/O controller for virtual pinball machines. (You can find the old version 1 software here.) Pinscape is software for the KL25Z that turns the board into a full-featured I/O controller for virtual pinball, with support for accelerometer-based nudging, a real plunger, button inputs, and feedback device control.

In case you haven't heard of the concept before, a "virtual pinball machine" is basically a video pinball simulator that's built into a real pinball machine body. A TV monitor goes in place of the pinball playfield, and a second TV goes in the backbox to serve as the "backglass" display. A third smaller monitor can serve as the "DMD" (the Dot Matrix Display used for scoring on newer machines), or you can even install a real pinball plasma DMD. A computer is hidden inside the cabinet, running pinball emulation software that displays a life-sized playfield on the main TV. The cabinet has all of the usual buttons, too, so it not only looks like the real thing, but plays like it too. That's a picture of my own machine to the right. On the outside, it's built exactly like a real arcade pinball machine, with the same overall dimensions and all of the standard pinball cabinet hardware.

A few small companies build and sell complete, finished virtual pinball machines, but I think it's more fun as a DIY project. If you have some basic wood-working skills and know your way around PCs, you can build one from scratch. The computer part is just an ordinary Windows PC, and all of the pinball emulation can be built out of free, open-source software. In that spirit, the Pinscape Controller is an open-source software/hardware project that offers a no-compromises, all-in-one control center for all of the unique input/output needs of a virtual pinball cabinet. If you've been thinking about building one of these, but you're not sure how to connect a plunger, flipper buttons, lights, nudge sensor, and whatever else you can think of, this project might be just what you're looking for.

You can find much more information about DIY Pin Cab building in general in the Virtual Cabinet Forum on vpforums.org. Also visit my Pinscape Resources page for more about this project and other virtual pinball projects I'm working on.

Downloads

  • Pinscape Release Builds: This page has download links for all of the Pinscape software. To get started, install and run the Pinscape Config Tool on your Windows computer. It will lead you through the steps for installing the Pinscape firmware on the KL25Z.
  • Config Tool Source Code. The complete C# source code for the config tool. You don't need this to run the tool, but it's available if you want to customize anything or see how it works inside.

Documentation

The new Version 2 Build Guide is now complete! This new version aims to be a complete guide to building a virtual pinball machine, including not only the Pinscape elements but all of the basics, from sourcing parts to building all of the hardware.

You can also refer to the original Hardware Build Guide (PDF), but that's out of date now, since it refers to the old version 1 software, which was rather different (especially when it comes to configuration).

System Requirements

The new config tool requires a fairly up-to-date Microsoft .NET installation. If you use Windows Update to keep your system current, you should be fine. A modern version of Internet Explorer (IE) is required, even if you don't use it as your main browser, because the config tool uses some system components that Microsoft packages into the IE install set. I test with IE11, so that's known to work. IE8 doesn't work. IE9 and 10 are unknown at this point.

The Windows requirements are only for the config tool. The firmware doesn't care about anything on the Windows side, so if you can make do without the config tool, you can use almost any Windows setup.

Main Features

Plunger: The Pinscape Controller started out as a "mechanical plunger" controller: a device for attaching a real pinball plunger to the video game software so that you could launch the ball the natural way. This is still, of course, a central feature of the project. The software supports several types of sensors: a high-resolution optical sensor (which works by essentially taking pictures of the plunger as it moves); a slide potentionmeter (which determines the position via the changing electrical resistance in the pot); a quadrature sensor (which counts bars printed on a special guide rail that it moves along); and an IR distance sensor (which determines the position by sending pulses of light at the plunger and measuring the round-trip travel time). The Build Guide explains how to set up each type of sensor.

Nudging: The KL25Z (the little microcontroller that the software runs on) has a built-in accelerometer. The Pinscape software uses it to sense when you nudge the cabinet, and feeds the acceleration data to the pinball software on the PC. This turns physical nudges into virtual English on the ball. The accelerometer is quite sensitive and accurate, so we can measure the difference between little bumps and hard shoves, and everything in between. The result is natural and immersive.

Buttons: You can wire real pinball buttons to the KL25Z, and the software will translate the buttons into PC input. You have the option to map each button to a keyboard key or joystick button. You can wire up your flipper buttons, Magna Save buttons, Start button, coin slots, operator buttons, and whatever else you need.

Feedback devices: You can also attach "feedback devices" to the KL25Z. Feedback devices are things that create tactile, sound, and lighting effects in sync with the game action. The most popular PC pinball emulators know how to address a wide variety of these devices, and know how to match them to on-screen action in each virtual table. You just need an I/O controller that translates commands from the PC into electrical signals that turn the devices on and off. The Pinscape Controller can do that for you.

Expansion Boards

There are two main ways to run the Pinscape Controller: standalone, or using the "expansion boards".

In the basic standalone setup, you just need the KL25Z, plus whatever buttons, sensors, and feedback devices you want to attach to it. This mode lets you take advantage of everything the software can do, but for some features, you'll have to build some ad hoc external circuitry to interface external devices with the KL25Z. The Build Guide has detailed plans for exactly what you need to build.

The other option is the Pinscape Expansion Boards. The expansion boards are a companion project, which is also totally free and open-source, that provides Printed Circuit Board (PCB) layouts that are designed specifically to work with the Pinscape software. The PCB designs are in the widely used EAGLE format, which many PCB manufacturers can turn directly into physical boards for you. The expansion boards organize all of the external connections more neatly than on the standalone KL25Z, and they add all of the interface circuitry needed for all of the advanced software functions. The big thing they bring to the table is lots of high-power outputs. The boards provide a modular system that lets you add boards to add more outputs. If you opt for the basic core setup, you'll have enough outputs for all of the toys in a really well-equipped cabinet. If your ambitions go beyond merely well-equipped and run to the ridiculously extravagant, just add an extra board or two. The modular design also means that you can add to the system over time.

Expansion Board project page

Update notes

If you have a Pinscape V1 setup already installed, you should be able to switch to the new version pretty seamlessly. There are just a couple of things to be aware of.

First, the "configuration" procedure is completely different in the new version. Way better and way easier, but it's not what you're used to from V1. In V1, you had to edit the project source code and compile your own custom version of the program. No more! With V2, you simply install the standard, pre-compiled .bin file, and select options using the Pinscape Config Tool on Windows.

Second, if you're using the TSL1410R optical sensor for your plunger, there's a chance you'll need to boost your light source's brightness a little bit. The "shutter speed" is faster in this version, which means that it doesn't spend as much time collecting light per frame as before. The software actually does "auto exposure" adaptation on every frame, so the increased shutter speed really shouldn't bother it, but it does require a certain minimum level of contrast, which requires a certain minimal level of lighting. Check the plunger viewer in the setup tool if you have any problems; if the image looks totally dark, try increasing the light level to see if that helps.

New Features

V2 has numerous new features. Here are some of the highlights...

Dynamic configuration: as explained above, configuration is now handled through the Config Tool on Windows. It's no longer necessary to edit the source code or compile your own modified binary.

Improved plunger sensing: the software now reads the TSL1410R optical sensor about 15x faster than it did before. This allows reading the sensor at full resolution (400dpi), about 400 times per second. The faster frame rate makes a big difference in how accurately we can read the plunger position during the fast motion of a release, which allows for more precise position sensing and faster response. The differences aren't dramatic, since the sensing was already pretty good even with the slower V1 scan rate, but you might notice a little better precision in tricky skill shots.

Keyboard keys: button inputs can now be mapped to keyboard keys. The joystick button option is still available as well, of course. Keyboard keys have the advantage of being closer to universal for PC pinball software: some pinball software can be set up to take joystick input, but nearly all PC pinball emulators can take keyboard input, and nearly all of them use the same key mappings.

Local shift button: one physical button can be designed as the local shift button. This works like a Shift button on a keyboard, but with cabinet buttons. It allows each physical button on the cabinet to have two PC keys assigned, one normal and one shifted. Hold down the local shift button, then press another key, and the other key's shifted key mapping is sent to the PC. The shift button can have a regular key mapping of its own as well, so it can do double duty. The shift feature lets you access more functions without cluttering your cabinet with extra buttons. It's especially nice for less frequently used functions like adjusting the volume or activating night mode.

Night mode: the output controller has a new "night mode" option, which lets you turn off all of your noisy devices with a single button, switch, or PC command. You can designate individual ports as noisy or not. Night mode only disables the noisemakers, so you still get the benefit of your flashers, button lights, and other quiet devices. This lets you play late into the night without disturbing your housemates or neighbors.

Gamma correction: you can designate individual output ports for gamma correction. This adjusts the intensity level of an output to make it match the way the human eye perceives brightness, so that fades and color mixes look more natural in lighting devices. You can apply this to individual ports, so that it only affects ports that actually have lights of some kind attached.

IR Remote Control: the controller software can transmit and/or receive IR remote control commands if you attach appropriate parts (an IR LED to send, an IR sensor chip to receive). This can be used to turn on your TV(s) when the system powers on, if they don't turn on automatically, and for any other functions you can think of requiring IR send/receive capabilities. You can assign IR commands to cabinet buttons, so that pressing a button on your cabinet sends a remote control command from the attached IR LED, and you can have the controller generate virtual key presses on your PC in response to received IR commands. If you have the IR sensor attached, the system can use it to learn commands from your existing remotes.

Yet more USB fixes: I've been gradually finding and fixing USB bugs in the mbed library for months now. This version has all of the fixes of the last couple of releases, of course, plus some new ones. It also has a new "last resort" feature, since there always seems to be "just one more" USB bug. The last resort is that you can tell the device to automatically reboot itself if it loses the USB connection and can't restore it within a given time limit.

More Downloads

  • Custom VP builds: I created modified versions of Visual Pinball 9.9 and Physmod5 that you might want to use in combination with this controller. The modified versions have special handling for plunger calibration specific to the Pinscape Controller, as well as some enhancements to the nudge physics. If you're not using the plunger, you might still want it for the nudge improvements. The modified version also works with any other input controller, so you can get the enhanced nudging effects even if you're using a different plunger/nudge kit. The big change in the modified versions is a "filter" for accelerometer input that's designed to make the response to cabinet nudges more realistic. It also makes the response more subdued than in the standard VP, so it's not to everyone's taste. The downloads include both the updated executables and the source code changes, in case you want to merge the changes into your own custom version(s).

    Note! These features are now standard in the official VP releases, so you don't need my custom builds if you're using 9.9.1 or later and/or VP 10. I don't think there's any reason to use my versions instead of the latest official ones, and in fact I'd encourage you to use the official releases since they're more up to date, but I'm leaving my builds available just in case. In the official versions, look for the checkbox "Enable Nudge Filter" in the Keys preferences dialog. My custom versions don't include that checkbox; they just enable the filter unconditionally.
  • Output circuit shopping list: This is a saved shopping cart at mouser.com with the parts needed to build one copy of the high-power output circuit for the LedWiz emulator feature, for use with the standalone KL25Z (that is, without the expansion boards). The quantities in the cart are for one output channel, so if you want N outputs, simply multiply the quantities by the N, with one exception: you only need one ULN2803 transistor array chip for each eight output circuits. If you're using the expansion boards, you won't need any of this, since the boards provide their own high-power outputs.
  • Cary Owens' optical sensor housing: A 3D-printable design for a housing/mounting bracket for the optical plunger sensor, designed by Cary Owens. This makes it easy to mount the sensor.
  • Lemming77's potentiometer mounting bracket and shooter rod connecter: Sketchup designs for 3D-printable parts for mounting a slide potentiometer as the plunger sensor. These were designed for a particular slide potentiometer that used to be available from an Aliexpress.com seller but is no longer listed. You can probably use this design as a starting point for other similar devices; just check the dimensions before committing the design to plastic.

Copyright and License

The Pinscape firmware is copyright 2014, 2021 by Michael J Roberts. It's released under an MIT open-source license. See License.

Warning to VirtuaPin Kit Owners

This software isn't designed as a replacement for the VirtuaPin plunger kit's firmware. If you bought the VirtuaPin kit, I recommend that you don't install this software. The VirtuaPin kit uses the same KL25Z microcontroller that Pinscape uses, but the rest of its hardware is different and incompatible. In particular, the Pinscape firmware doesn't include support for the IR proximity sensor used in the VirtuaPin plunger kit, so you won't be able to use your plunger device with the Pinscape firmware. In addition, the VirtuaPin setup uses a different set of GPIO pins for the button inputs from the Pinscape defaults, so if you do install the Pinscape firmware, you'll have to go into the Config Tool and reassign all of the buttons to match the VirtuaPin wiring.

Committer:
mjr
Date:
Fri Apr 21 18:50:37 2017 +0000
Revision:
86:e30a1f60f783
Parent:
82:4f6209cb5c33
Child:
87:8d35c74403af
Capture a bunch of alternative bar code decoder tests, mostly unsuccessful

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mjr 82:4f6209cb5c33 1 /*
mjr 82:4f6209cb5c33 2 * AMS/TAOS TSL14xx series photodiode array interface class.
mjr 82:4f6209cb5c33 3 *
mjr 82:4f6209cb5c33 4 * This provides a high-level interface for the AMS/TAOS TSLxx series
mjr 82:4f6209cb5c33 5 * of photodiode arrays. This class works with most of the sensors
mjr 82:4f6209cb5c33 6 * in this series, which differ only in pixel array sizes. This code
mjr 82:4f6209cb5c33 7 * has been tested with the following sensors from the series:
mjr 82:4f6209cb5c33 8 *
mjr 82:4f6209cb5c33 9 * TSL1410R - 1280 pixels, 400dpi
mjr 82:4f6209cb5c33 10 * TSL1412S - 1536 pixels, 400dpi
mjr 82:4f6209cb5c33 11 * TSL1401CL - 128 pixels, 400dpi
mjr 82:4f6209cb5c33 12 *
mjr 82:4f6209cb5c33 13 * All of these sensors have the same electrical interface, consisting
mjr 82:4f6209cb5c33 14 * of a clock input (CLK), start pulse input (SI), and analog pixel
mjr 82:4f6209cb5c33 15 * output (AO). The sensors are equipped with hold capacitors and
mjr 82:4f6209cb5c33 16 * shift registers that allow simultaneous sampling of all pixels, and
mjr 82:4f6209cb5c33 17 * serial access to the pixel values.
mjr 82:4f6209cb5c33 18 *
mjr 82:4f6209cb5c33 19 * (Note on the plunger sensor class hierarchy: this class is for the
mjr 82:4f6209cb5c33 20 * sensor only, not for the plunger application. This class is meant
mjr 82:4f6209cb5c33 21 * to be reusable in other contexts that just need to read raw pixel
mjr 82:4f6209cb5c33 22 * data from the sensor. Plunger/tslxxSensor.h implements the next
mjr 82:4f6209cb5c33 23 * level up, which is the implementation of the generic plunger sensor
mjr 82:4f6209cb5c33 24 * interface for TSL14xx sensors. That's still an abstract class, since
mjr 82:4f6209cb5c33 25 * it only provides the plunger class specialization for these sensor
mjr 82:4f6209cb5c33 26 * types, without any image analysis component. The final concrete
mjr 82:4f6209cb5c33 27 * classes are in Plunger/edgeSensor.h and Plunger/barCodeSensor.h,
mjr 82:4f6209cb5c33 28 * which add the image processing that analyzes the image data to
mjr 82:4f6209cb5c33 29 * determine the plunger position.)
mjr 82:4f6209cb5c33 30 *
mjr 82:4f6209cb5c33 31 * Our API is based on a double-buffered asynchronous read. The caller
mjr 82:4f6209cb5c33 32 * can access a completed buffer, containing the pixels from the last image
mjr 82:4f6209cb5c33 33 * frame, while the sensor is transferring data asynchronously (using the
mjr 82:4f6209cb5c33 34 * microcontroller's DMA capability) into the other buffer. Each time a
mjr 82:4f6209cb5c33 35 * new read is started, we swap buffers, making the last completed buffer
mjr 82:4f6209cb5c33 36 * available to the client and handing the other buffer to the DMA
mjr 82:4f6209cb5c33 37 * controller to fill asynchronously.
mjr 82:4f6209cb5c33 38 *
mjr 82:4f6209cb5c33 39 * The photodiodes in these sensors gather light very rapidly, allowing
mjr 82:4f6209cb5c33 40 * for extremely short exposure times. The "shutter" is electronic;
mjr 82:4f6209cb5c33 41 * a signal on the pulse input resets the pixels and begins an integration
mjr 82:4f6209cb5c33 42 * period, and a subsequent signal ends the integration and transfers the
mjr 82:4f6209cb5c33 43 * pixel voltages to the hold capacitors. Minimum exposure times are less
mjr 82:4f6209cb5c33 44 * than a millisecond. The actual timing is under software control, since
mjr 82:4f6209cb5c33 45 * we determine the start and end of the integration period via the pulse
mjr 82:4f6209cb5c33 46 * input. Longer integration periods gather more light, like a longer
mjr 82:4f6209cb5c33 47 * exposure on a conventional camera. For our purposes in the Pinscape
mjr 82:4f6209cb5c33 48 * Controller, we want the highest possible frame rate, as we're trying to
mjr 82:4f6209cb5c33 49 * capture the motion of a fast-moving object (the plunger). The KL25Z
mjr 82:4f6209cb5c33 50 * can't actually keep up with shortest integration time the sensor can
mjr 82:4f6209cb5c33 51 * achieve - the limiting factor is the KL25Z ADC, which needs at least
mjr 82:4f6209cb5c33 52 * 2.5us to collect each sample. The sensor transfers pixels to the MCU
mjr 82:4f6209cb5c33 53 * serially, and each pixel is transferred as an analog voltage level, so
mjr 82:4f6209cb5c33 54 * we have to collect one ADC sample per pixel. Our maximum frame rate
mjr 82:4f6209cb5c33 55 * is therefore determined by the product of the minimum ADC sample time
mjr 82:4f6209cb5c33 56 * and the number of pixels.
mjr 82:4f6209cb5c33 57 *
mjr 82:4f6209cb5c33 58 * The fastest operating mode for the KL25Z ADC is its "continuous"
mjr 82:4f6209cb5c33 59 * mode, where it automatically starts taking a new sample every time
mjr 82:4f6209cb5c33 60 * it completes the previous one. The fastest way to transfer the
mjr 82:4f6209cb5c33 61 * samples to memory in this mode is via the hardware DMA controller.
mjr 82:4f6209cb5c33 62 *
mjr 82:4f6209cb5c33 63 * It takes a pretty tricky setup to make this work. I don't like tricky
mjr 82:4f6209cb5c33 64 * setups - I prefer something easy to understand - but in this case it's
mjr 82:4f6209cb5c33 65 * justified because of the importance in this application of maximizing
mjr 82:4f6209cb5c33 66 * the frame rate. I'm pretty sure there's no other way to even get close
mjr 82:4f6209cb5c33 67 * to the rate we can achieve with the continuous ADC/DMA combination.
mjr 82:4f6209cb5c33 68 * The ADC/DMA mode gives us pixel read times of about 2us, vs a minimum
mjr 82:4f6209cb5c33 69 * of about 14us for the next best method I've found. Using this mode, we
mjr 82:4f6209cb5c33 70 * can read the TSL1410R's 1280 pixels at full resolution in about 2.5ms.
mjr 82:4f6209cb5c33 71 * That's a frame rate of 400 frames per second, which is fast enough to
mjr 82:4f6209cb5c33 72 * capture a fast-moving plunger with minimal motion blur.
mjr 82:4f6209cb5c33 73 *
mjr 82:4f6209cb5c33 74 * Note that some of the sensors in this series (TSL1410R, TSL1412S) have
mjr 82:4f6209cb5c33 75 * a "parallel" readout mode that lets them physically deliver two pixels
mjr 82:4f6209cb5c33 76 * at once the MCU, via separate physical connections. This could provide
mjr 82:4f6209cb5c33 77 * a 2X speedup on an MCU equipped with two independent ADC samplers.
mjr 82:4f6209cb5c33 78 * Unfortunately, the KL25Z is not so equipped; even though it might appear
mjr 82:4f6209cb5c33 79 * at first glance to support multiple ADC "channels", all of the channels
mjr 82:4f6209cb5c33 80 * internally connect to a single ADC sampler, so the hardware can ultimately
mjr 82:4f6209cb5c33 81 * perform only one conversion at a time. Paradoxically, using the sensor's
mjr 82:4f6209cb5c33 82 * parallel mode is actually *slower* with a KL25Z than using its serial
mjr 82:4f6209cb5c33 83 * mode, because we can only maintain the higher throughput of the KL25Z
mjr 82:4f6209cb5c33 84 * ADC's "continuous sampling mode" by reading all samples thorugh a single
mjr 82:4f6209cb5c33 85 * channel.
mjr 82:4f6209cb5c33 86 *
mjr 82:4f6209cb5c33 87 * Here's the tricky approach we use:
mjr 82:4f6209cb5c33 88 *
mjr 82:4f6209cb5c33 89 * First, we put the analog input port (the ADC == Analog-to-Digital
mjr 82:4f6209cb5c33 90 * Converter) in "continuous" mode, at the highest clock speed we can
mjr 82:4f6209cb5c33 91 * program with the available clocks and the fastest read cycle
mjr 82:4f6209cb5c33 92 * available in the ADC hardware. (The analog input port is the
mjr 82:4f6209cb5c33 93 * GPIO pin attached to the sensor's AO == Analog Output pin, where
mjr 82:4f6209cb5c33 94 * it outputs each pixel's value, one at a time, as an analog voltage
mjr 82:4f6209cb5c33 95 * level.) In continuous mode, every time the ADC finishes taking a
mjr 82:4f6209cb5c33 96 * sample, it stores the result value in its output register and then
mjr 82:4f6209cb5c33 97 * immediately starts taking a new sample. This means that no MCU
mjr 82:4f6209cb5c33 98 * (or even DMA) action is required to start each new sample. This
mjr 82:4f6209cb5c33 99 * is where most of the speedup comes from, since it takes significant
mjr 82:4f6209cb5c33 100 * time (multiple microseconds) to move data through the peripheral
mjr 82:4f6209cb5c33 101 * registers, and it takes more time (also multiple microseconds) for
mjr 82:4f6209cb5c33 102 * the ADC to spin up for each new sample when in single-sample mode.
mjr 82:4f6209cb5c33 103 * We cut out about 7us this way and get the time per sample down to
mjr 82:4f6209cb5c33 104 * about 2us. This is close to the documented maximum speed for the
mjr 82:4f6209cb5c33 105 * ADC hardware.
mjr 82:4f6209cb5c33 106 *
mjr 82:4f6209cb5c33 107 * Second, we use the DMA controller to read the ADC result register
mjr 82:4f6209cb5c33 108 * and store each sample in a memory array for processing. The ADC
mjr 82:4f6209cb5c33 109 * hardware is designed to work with the DMA controller by signaling
mjr 82:4f6209cb5c33 110 * the DMA controller when a new sample is ready; this allows DMA to
mjr 82:4f6209cb5c33 111 * move each sample immediately when it's available without any CPU
mjr 82:4f6209cb5c33 112 * involvement.
mjr 82:4f6209cb5c33 113 *
mjr 82:4f6209cb5c33 114 * Third - and this is where it really gets tricky - we use two
mjr 82:4f6209cb5c33 115 * additional "linked" DMA channels to generate the clock signal
mjr 82:4f6209cb5c33 116 * to the CCD sensor. The clock signal is how we tell the CCD when
mjr 82:4f6209cb5c33 117 * to place the next pixel voltage on its AO pin, so the clock has
mjr 82:4f6209cb5c33 118 * to be generated in lock step with the ADC sampling cycle. The
mjr 82:4f6209cb5c33 119 * ADC timing isn't perfectly uniform or predictable, so we can't
mjr 82:4f6209cb5c33 120 * just generate the pixel clock with a *real* clock. We have to
mjr 82:4f6209cb5c33 121 * time the signal exactly with the ADC, which means that we have
mjr 82:4f6209cb5c33 122 * to generate it from the ADC "sample is ready" signal. Fortunately,
mjr 82:4f6209cb5c33 123 * there is just such a signal, and in fact we're already using it,
mjr 82:4f6209cb5c33 124 * as described above, to tell the DMA when to move each result from
mjr 82:4f6209cb5c33 125 * the ADC output register to our memory array. So how do we use this
mjr 82:4f6209cb5c33 126 * to generate the CCD clock? The answer lies in the DMA controller's
mjr 82:4f6209cb5c33 127 * channel linking feature. This allows one DMA channel to trigger a
mjr 82:4f6209cb5c33 128 * second DMA channel each time the first channel completes one
mjr 82:4f6209cb5c33 129 * transfer. And we can use DMA to control our clock GPIO pin by
mjr 82:4f6209cb5c33 130 * using the pin's GPIO IPORT register as the DMA destination address.
mjr 82:4f6209cb5c33 131 * Specifically, we can take the clock high by writing our pin's bit
mjr 82:4f6209cb5c33 132 * pattern to the PSOR ("set output") register, and we can take the
mjr 82:4f6209cb5c33 133 * clock low by writing to the PCOR ("clear output") register. We
mjr 82:4f6209cb5c33 134 * use one DMA channel for each of these operations.
mjr 82:4f6209cb5c33 135 *
mjr 82:4f6209cb5c33 136 * Putting it all together, the cascade of linked DMA channels
mjr 82:4f6209cb5c33 137 * works like this:
mjr 82:4f6209cb5c33 138 *
mjr 82:4f6209cb5c33 139 * - We kick off the first ADC sample.
mjr 82:4f6209cb5c33 140 *
mjr 82:4f6209cb5c33 141 * - When the ADC sample completes, the ADC DMA trigger fires,
mjr 82:4f6209cb5c33 142 * which triggers channel 1, the "Clock Up" channel. This
mjr 82:4f6209cb5c33 143 * performs one transfer of the clock GPIO bit to the clock
mjr 82:4f6209cb5c33 144 * PSOR register, taking the clock high, which causes the CCD
mjr 82:4f6209cb5c33 145 * to move the next pixel onto AO.
mjr 82:4f6209cb5c33 146 *
mjr 82:4f6209cb5c33 147 * - After the Clock Up channel does its transfer, it triggers
mjr 82:4f6209cb5c33 148 * its link to channel 2, the ADC transfer channel. This
mjr 82:4f6209cb5c33 149 * channel moves the ADC output register value to our memory
mjr 82:4f6209cb5c33 150 * array.
mjr 82:4f6209cb5c33 151 *
mjr 82:4f6209cb5c33 152 * - After the ADC channel does its transfer, it triggers channel
mjr 82:4f6209cb5c33 153 * 3, the "Clock Down" channel. This performs one transfer of
mjr 82:4f6209cb5c33 154 * the clock GPIO bit to the clock PCOR register, taking the
mjr 82:4f6209cb5c33 155 * clock low.
mjr 82:4f6209cb5c33 156 *
mjr 82:4f6209cb5c33 157 * Note that the order of the channels - Clock Up, ADC, Clock Down -
mjr 82:4f6209cb5c33 158 * is important. It ensures that we don't toggle the clock line
mjr 82:4f6209cb5c33 159 * too quickly. The CCD has a minimum pulse duration of 50ns for
mjr 82:4f6209cb5c33 160 * the clock signal. The DMA controller is so fast that it might
mjr 82:4f6209cb5c33 161 * toggle the clock faster than this limit if we did the Up and
mjr 82:4f6209cb5c33 162 * Down transfers back-to-back.
mjr 82:4f6209cb5c33 163 *
mjr 82:4f6209cb5c33 164 * Note also that it's important for Clock Up to be the very first
mjr 82:4f6209cb5c33 165 * operation after the DMA trigger. The ADC is in continuous mode,
mjr 82:4f6209cb5c33 166 * meaning that it starts taking a new sample immediately upon
mjr 82:4f6209cb5c33 167 * finishing the previous one. So when the ADC DMA signal fires,
mjr 82:4f6209cb5c33 168 * the new sample is already starting. We therefore have to get
mjr 82:4f6209cb5c33 169 * the next pixel onto the sampling pin immediately, or as close
mjr 82:4f6209cb5c33 170 * to immediately as possible. The sensor's "analog output
mjr 82:4f6209cb5c33 171 * settling time" is 120ns - this is the time for a new pixel
mjr 82:4f6209cb5c33 172 * voltage to stabilize on AO after a clock rising edge. So
mjr 82:4f6209cb5c33 173 * assuming that the ADC raises the DMA signal immediately on
mjr 82:4f6209cb5c33 174 * sample completion, and the DMA controller responds within a
mjr 82:4f6209cb5c33 175 * couple of MCU clock cycles, we should have the new pixel voltage
mjr 82:4f6209cb5c33 176 * stable on the sampling pin by about 200ns after the new ADC
mjr 82:4f6209cb5c33 177 * sample cycle starts. The sampling cycle with our current
mjr 82:4f6209cb5c33 178 * parameters is about 2us, so the voltage level is stable for
mjr 82:4f6209cb5c33 179 * 90% of the cycle.
mjr 82:4f6209cb5c33 180 *
mjr 82:4f6209cb5c33 181 * Also, note that it's okay that the ADC sample transfer doesn't
mjr 82:4f6209cb5c33 182 * happen until after the Clock Up DMA transfer. The ADC output
mjr 82:4f6209cb5c33 183 * register holds the last result until the next sample completes,
mjr 82:4f6209cb5c33 184 * so we have about 2us to grab it. The first Clock Up DMA
mjr 82:4f6209cb5c33 185 * transfer only takes a couple of clocks - order of 100ns - so
mjr 82:4f6209cb5c33 186 * we get to it with time to spare.
mjr 82:4f6209cb5c33 187 *
mjr 82:4f6209cb5c33 188 * (Note that it would nicer to handle the clock with a single DMA
mjr 82:4f6209cb5c33 189 * channel, since DMA channels are a limited resource. We could
mjr 82:4f6209cb5c33 190 * conceivably consolidate the clock generator one DMA channel by
mjr 82:4f6209cb5c33 191 * switching the DMA destination to the PTOR "toggle" register, and
mjr 82:4f6209cb5c33 192 * writing *two* times per trigger - once to toggle the clock up,
mjr 82:4f6209cb5c33 193 * and a second time to toggle it down. But I haven't found a way
mjr 82:4f6209cb5c33 194 * to make this work. The obstacle is that the DMA controller can
mjr 82:4f6209cb5c33 195 * only do one transfer per trigger in the fully autonomous mode
mjr 82:4f6209cb5c33 196 * we're using, and to make this toggle scheme work, we'd have to do
mjr 82:4f6209cb5c33 197 * two writes per trigger. Maybe even three or four: I think we'd
mjr 82:4f6209cb5c33 198 * have to throw in one or two no-op writes (of all zeroes) between
mjr 82:4f6209cb5c33 199 * the two toggles, to pad the timing to ensure that the clock pulse
mjr 82:4f6209cb5c33 200 * width is over the sensor's 50ns minimum. But it's the same issue
mjr 82:4f6209cb5c33 201 * whether it's two writes or four. The DMA controller does have a
mjr 82:4f6209cb5c33 202 * "continuous" mode that does an entire transfer on a single trigger,
mjr 82:4f6209cb5c33 203 * but it can't reset itself after such a transfer; CPU intervention
mjr 82:4f6209cb5c33 204 * is required to do that, which means we'd have to service an
mjr 82:4f6209cb5c33 205 * interrupt on every ADC cycle to set up the next clock write.
mjr 82:4f6209cb5c33 206 * Given the 2us cycle time, an interrupt would create a ton of CPU
mjr 82:4f6209cb5c33 207 * load, and I don't think the CPU is fast enough to reliably complete
mjr 82:4f6209cb5c33 208 * the work we'd have to do on each 2us cycle. Fortunately, at
mjr 82:4f6209cb5c33 209 * the moment we can afford to dedicate three channels to this
mjr 82:4f6209cb5c33 210 * module. We only have one other module using the DMA at all
mjr 82:4f6209cb5c33 211 * (the TLC5940 PWM controller interface), and it only needs one
mjr 82:4f6209cb5c33 212 * channel. So the KL25Z's complement of four DMA channels is just
mjr 82:4f6209cb5c33 213 * enough for all of our needs for the moment.)
mjr 82:4f6209cb5c33 214 */
mjr 82:4f6209cb5c33 215
mjr 82:4f6209cb5c33 216 #include "mbed.h"
mjr 82:4f6209cb5c33 217 #include "config.h"
mjr 82:4f6209cb5c33 218 #include "AltAnalogIn.h"
mjr 82:4f6209cb5c33 219 #include "SimpleDMA.h"
mjr 82:4f6209cb5c33 220 #include "DMAChannels.h"
mjr 82:4f6209cb5c33 221
mjr 82:4f6209cb5c33 222 #ifndef TSL14XX_H
mjr 82:4f6209cb5c33 223 #define TSL14XX_H
mjr 82:4f6209cb5c33 224
mjr 82:4f6209cb5c33 225
mjr 82:4f6209cb5c33 226 // To allow DMA access to the clock pin, we need to point the DMA
mjr 82:4f6209cb5c33 227 // controller to the IOPORT registers that control the pin. PORT_BASE()
mjr 82:4f6209cb5c33 228 // gives us the address of the register group for the 32 GPIO pins with
mjr 82:4f6209cb5c33 229 // the same letter name as our target pin (e.g., PTA0 through PTA31),
mjr 82:4f6209cb5c33 230 // and PINMASK gives us the bit pattern to write to those registers to
mjr 82:4f6209cb5c33 231 // access our single GPIO pin. Each register group has three special
mjr 82:4f6209cb5c33 232 // registers that update the pin in particular ways: PSOR ("set output
mjr 82:4f6209cb5c33 233 // register") turns pins on, PCOR ("clear output register") turns pins
mjr 82:4f6209cb5c33 234 // off, and PTOR ("toggle output register") toggle pins to the opposite
mjr 82:4f6209cb5c33 235 // of their current values. These registers have special semantics:
mjr 82:4f6209cb5c33 236 // writing a bit as 0 has no effect on the corresponding pin, while
mjr 82:4f6209cb5c33 237 // writing a bit as 1 performs the register's action on the pin. This
mjr 82:4f6209cb5c33 238 // allows a single GPIO pin to be set, cleared, or toggled with a
mjr 82:4f6209cb5c33 239 // 32-bit write to one of these registers, without affecting any of the
mjr 82:4f6209cb5c33 240 // other pins addressed by the register. (It also allows changing any
mjr 82:4f6209cb5c33 241 // group of pins with a single write, although we don't use that
mjr 82:4f6209cb5c33 242 // feature here.)
mjr 82:4f6209cb5c33 243 //
mjr 82:4f6209cb5c33 244 // - To turn a pin ON: PORT_BASE(pin)->PSOR = PINMASK(pin)
mjr 82:4f6209cb5c33 245 // - To turn a pin OFF: PORT_BASE(pin)->PCOR = PINMASK(pin)
mjr 82:4f6209cb5c33 246 // - To toggle a pin: PORT_BASE(pin)->PTOR = PINMASK(pin)
mjr 82:4f6209cb5c33 247 //
mjr 82:4f6209cb5c33 248 #define GPIO_PORT(pin) (((unsigned int)(pin)) >> PORT_SHIFT)
mjr 82:4f6209cb5c33 249 #define GPIO_PORT_BASE(pin) ((GPIO_Type *)(PTA_BASE + GPIO_PORT(pin) * 0x40))
mjr 82:4f6209cb5c33 250 #define GPIO_PINMASK(pin) gpio_set(pin)
mjr 82:4f6209cb5c33 251
mjr 82:4f6209cb5c33 252 IF_DIAG(
mjr 82:4f6209cb5c33 253 extern uint64_t mainLoopIterCheckpt[];
mjr 82:4f6209cb5c33 254 extern Timer mainLoopTimer;)
mjr 82:4f6209cb5c33 255
mjr 82:4f6209cb5c33 256 class TSL14xx
mjr 82:4f6209cb5c33 257 {
mjr 82:4f6209cb5c33 258 public:
mjr 82:4f6209cb5c33 259 // Set up the interface.
mjr 82:4f6209cb5c33 260 //
mjr 82:4f6209cb5c33 261 // nPixSensor = native number of pixels on sensor
mjr 82:4f6209cb5c33 262 // siPin = SI pin (GPIO, digital out)
mjr 82:4f6209cb5c33 263 // clockPin = CLK pin (GPIO, digital out)
mjr 82:4f6209cb5c33 264 // aoPin = AO pin (GPIO, analog in - must be ADC-capable)
mjr 82:4f6209cb5c33 265 TSL14xx(int nPixSensor, PinName siPin, PinName clockPin, PinName aoPin)
mjr 82:4f6209cb5c33 266 : adc_dma(DMAch_ADC),
mjr 82:4f6209cb5c33 267 clkUp_dma(DMAch_CLKUP),
mjr 82:4f6209cb5c33 268 clkDn_dma(DMAch_CLKDN),
mjr 82:4f6209cb5c33 269 si(siPin),
mjr 82:4f6209cb5c33 270 clock(clockPin),
mjr 82:4f6209cb5c33 271 ao(aoPin, true),
mjr 82:4f6209cb5c33 272 nPixSensor(nPixSensor)
mjr 82:4f6209cb5c33 273 {
mjr 82:4f6209cb5c33 274 // start the sample timer with an arbitrary zero point of 'now'
mjr 82:4f6209cb5c33 275 t.start();
mjr 82:4f6209cb5c33 276
mjr 82:4f6209cb5c33 277 // allocate our double pixel buffers
mjr 82:4f6209cb5c33 278 pix1 = new uint8_t[nPixSensor*2];
mjr 82:4f6209cb5c33 279 pix2 = pix1 + nPixSensor;
mjr 82:4f6209cb5c33 280
mjr 82:4f6209cb5c33 281 // put the first DMA transfer into the first buffer (pix1)
mjr 82:4f6209cb5c33 282 pixDMA = 0;
mjr 82:4f6209cb5c33 283 running = false;
mjr 82:4f6209cb5c33 284
mjr 82:4f6209cb5c33 285 // remember the clock pin port base and pin mask for fast access
mjr 82:4f6209cb5c33 286 clockPort = GPIO_PORT_BASE(clockPin);
mjr 82:4f6209cb5c33 287 clockMask = GPIO_PINMASK(clockPin);
mjr 82:4f6209cb5c33 288
mjr 82:4f6209cb5c33 289 // clear out power-on random data by clocking through all pixels twice
mjr 82:4f6209cb5c33 290 clear();
mjr 82:4f6209cb5c33 291 clear();
mjr 82:4f6209cb5c33 292
mjr 82:4f6209cb5c33 293 // Set up the Clock Up DMA channel. This channel takes the
mjr 82:4f6209cb5c33 294 // clock high by writing the clock bit to the PSOR (set output)
mjr 82:4f6209cb5c33 295 // register for the clock pin.
mjr 82:4f6209cb5c33 296 clkUp_dma.source(&clockMask, false, 32);
mjr 82:4f6209cb5c33 297 clkUp_dma.destination(&clockPort->PSOR, false, 32);
mjr 82:4f6209cb5c33 298
mjr 82:4f6209cb5c33 299 // Set up the Clock Down DMA channel. This channel takes the
mjr 82:4f6209cb5c33 300 // clock low by writing the clock bit to the PCOR (clear output)
mjr 82:4f6209cb5c33 301 // register for the clock pin.
mjr 82:4f6209cb5c33 302 clkDn_dma.source(&clockMask, false, 32);
mjr 82:4f6209cb5c33 303 clkDn_dma.destination(&clockPort->PCOR, false, 32);
mjr 82:4f6209cb5c33 304
mjr 82:4f6209cb5c33 305 // Set up the ADC transfer DMA channel. This channel transfers
mjr 82:4f6209cb5c33 306 // the current analog sampling result from the ADC output register
mjr 82:4f6209cb5c33 307 // to our pixel array.
mjr 82:4f6209cb5c33 308 ao.initDMA(&adc_dma);
mjr 82:4f6209cb5c33 309
mjr 82:4f6209cb5c33 310 // Set up our chain of linked DMA channel:
mjr 82:4f6209cb5c33 311 //
mjr 82:4f6209cb5c33 312 // ADC sample completion triggers Clock Up
mjr 82:4f6209cb5c33 313 // ...which triggers the ADC transfer
mjr 82:4f6209cb5c33 314 // ...which triggers Clock Down
mjr 82:4f6209cb5c33 315 //
mjr 82:4f6209cb5c33 316 // We operate the ADC in "continuous mode", meaning that it starts
mjr 82:4f6209cb5c33 317 // a new sample immediately after the last one completes. This is
mjr 82:4f6209cb5c33 318 // what keeps the cycle going after the Clock Down, since the Clock
mjr 82:4f6209cb5c33 319 // Down transfer itself doesn't trigger another DMA operation.
mjr 82:4f6209cb5c33 320 clkUp_dma.trigger(Trigger_ADC0);
mjr 82:4f6209cb5c33 321 clkUp_dma.link(adc_dma);
mjr 82:4f6209cb5c33 322 adc_dma.link(clkDn_dma, false);
mjr 82:4f6209cb5c33 323
mjr 82:4f6209cb5c33 324 // Set the trigger on the downstream links to NONE - these are
mjr 82:4f6209cb5c33 325 // triggered by their upstream links, so they don't need separate
mjr 82:4f6209cb5c33 326 // peripheral or software triggers.
mjr 82:4f6209cb5c33 327 adc_dma.trigger(Trigger_NONE);
mjr 82:4f6209cb5c33 328 clkDn_dma.trigger(Trigger_NONE);
mjr 82:4f6209cb5c33 329
mjr 82:4f6209cb5c33 330 // Register an interrupt callback so that we're notified when
mjr 82:4f6209cb5c33 331 // the last transfer completes.
mjr 82:4f6209cb5c33 332 clkDn_dma.attach(this, &TSL14xx::transferDone);
mjr 82:4f6209cb5c33 333
mjr 82:4f6209cb5c33 334 // clear the timing statistics
mjr 82:4f6209cb5c33 335 totalTime = 0.0;
mjr 82:4f6209cb5c33 336 nRuns = 0;
mjr 82:4f6209cb5c33 337 }
mjr 82:4f6209cb5c33 338
mjr 82:4f6209cb5c33 339 // Get the stable pixel array. This is the image array from the
mjr 82:4f6209cb5c33 340 // previous capture. It remains valid until the next startCapture()
mjr 82:4f6209cb5c33 341 // call, at which point this buffer will be reused for the new capture.
mjr 82:4f6209cb5c33 342 void getPix(uint8_t * &pix, uint32_t &t)
mjr 82:4f6209cb5c33 343 {
mjr 82:4f6209cb5c33 344 // return the pixel array that ISN'T assigned to the DMA
mjr 82:4f6209cb5c33 345 if (pixDMA)
mjr 82:4f6209cb5c33 346 {
mjr 82:4f6209cb5c33 347 // DMA owns pix2, so the stable array is pix1
mjr 82:4f6209cb5c33 348 pix = pix1;
mjr 82:4f6209cb5c33 349 t = t1;
mjr 82:4f6209cb5c33 350 }
mjr 82:4f6209cb5c33 351 else
mjr 82:4f6209cb5c33 352 {
mjr 82:4f6209cb5c33 353 // DMA owns pix1, so the stable array is pix2
mjr 82:4f6209cb5c33 354 pix = pix2;
mjr 82:4f6209cb5c33 355 t = t2;
mjr 82:4f6209cb5c33 356 }
mjr 82:4f6209cb5c33 357 }
mjr 82:4f6209cb5c33 358
mjr 86:e30a1f60f783 359 // Wait for the current DMA transfer to finish, and retrieve its
mjr 86:e30a1f60f783 360 // pixel array buffer. This provides access to the latest image
mjr 86:e30a1f60f783 361 // without starting a new transfer. These pixels are valid throughout
mjr 86:e30a1f60f783 362 // the next transfer (started via startCapture()) and remain valid
mjr 86:e30a1f60f783 363 // until the next transfer after that.
mjr 86:e30a1f60f783 364 void waitPix(uint8_t * &pix, uint32_t &t)
mjr 86:e30a1f60f783 365 {
mjr 86:e30a1f60f783 366 // wait for the current transfer to finish
mjr 86:e30a1f60f783 367 wait();
mjr 86:e30a1f60f783 368
mjr 86:e30a1f60f783 369 // Return the pixel array that IS assigned to DMA, since this
mjr 86:e30a1f60f783 370 // is the latest buffer filled. This buffer is stable, even
mjr 86:e30a1f60f783 371 // though it's assigned to DMA, because the last transfer is
mjr 86:e30a1f60f783 372 // already finished and thus DMA is no longer accessing the
mjr 86:e30a1f60f783 373 // buffer.
mjr 86:e30a1f60f783 374 if (pixDMA)
mjr 86:e30a1f60f783 375 {
mjr 86:e30a1f60f783 376 // DMA owns pix2
mjr 86:e30a1f60f783 377 pix = pix2;
mjr 86:e30a1f60f783 378 t = t2;
mjr 86:e30a1f60f783 379 }
mjr 86:e30a1f60f783 380 else
mjr 86:e30a1f60f783 381 {
mjr 86:e30a1f60f783 382 // DMA owns pix1
mjr 86:e30a1f60f783 383 pix = pix1;
mjr 86:e30a1f60f783 384 t = t1;
mjr 86:e30a1f60f783 385 }
mjr 86:e30a1f60f783 386 }
mjr 86:e30a1f60f783 387
mjr 82:4f6209cb5c33 388 // Start an image capture from the sensor. Waits the previous
mjr 82:4f6209cb5c33 389 // capture to finish if it's still running, then starts a new one
mjr 82:4f6209cb5c33 390 // and returns immediately. The new capture proceeds autonomously
mjr 82:4f6209cb5c33 391 // via the DMA hardware, so the caller can continue with other
mjr 82:4f6209cb5c33 392 // processing during the capture.
mjr 82:4f6209cb5c33 393 void startCapture(uint32_t minIntTime_us = 0)
mjr 82:4f6209cb5c33 394 {
mjr 82:4f6209cb5c33 395 IF_DIAG(uint32_t tDiag0 = mainLoopTimer.read_us();)
mjr 82:4f6209cb5c33 396
mjr 82:4f6209cb5c33 397 // wait for the last current capture to finish
mjr 82:4f6209cb5c33 398 while (running) { }
mjr 82:4f6209cb5c33 399
mjr 82:4f6209cb5c33 400 // we're starting a new capture immediately
mjr 82:4f6209cb5c33 401 running = true;
mjr 82:4f6209cb5c33 402
mjr 82:4f6209cb5c33 403 // collect timing diagnostics
mjr 82:4f6209cb5c33 404 IF_DIAG(mainLoopIterCheckpt[8] += uint32_t(mainLoopTimer.read_us() - tDiag0);)
mjr 82:4f6209cb5c33 405
mjr 82:4f6209cb5c33 406 // If the elapsed time since the start of the last integration
mjr 82:4f6209cb5c33 407 // hasn't reached the specified minimum yet, wait. This allows
mjr 82:4f6209cb5c33 408 // the caller to control the integration time to optimize the
mjr 82:4f6209cb5c33 409 // exposure level.
mjr 82:4f6209cb5c33 410 uint32_t dt = uint32_t(t.read_us() - tInt);
mjr 82:4f6209cb5c33 411 if (dt < minIntTime_us)
mjr 82:4f6209cb5c33 412 {
mjr 82:4f6209cb5c33 413 // we haven't reached the required minimum yet - wait for the
mjr 82:4f6209cb5c33 414 // remaining interval
mjr 82:4f6209cb5c33 415 wait_us(minIntTime_us - dt);
mjr 82:4f6209cb5c33 416 }
mjr 82:4f6209cb5c33 417
mjr 82:4f6209cb5c33 418 // swap to the other DMA buffer for reading the new pixel samples
mjr 82:4f6209cb5c33 419 pixDMA ^= 1;
mjr 82:4f6209cb5c33 420
mjr 82:4f6209cb5c33 421 // Set up the active pixel array as the destination buffer for
mjr 82:4f6209cb5c33 422 // the ADC DMA channel.
mjr 82:4f6209cb5c33 423 adc_dma.destination(pixDMA ? pix2 : pix1, true);
mjr 82:4f6209cb5c33 424
mjr 82:4f6209cb5c33 425 // start the DMA transfers
mjr 82:4f6209cb5c33 426 clkDn_dma.start(nPixSensor*4, true);
mjr 82:4f6209cb5c33 427 adc_dma.start(nPixSensor, true);
mjr 82:4f6209cb5c33 428 clkUp_dma.start(nPixSensor*4, true);
mjr 82:4f6209cb5c33 429
mjr 82:4f6209cb5c33 430 // note the start time of this transfer
mjr 82:4f6209cb5c33 431 t0 = t.read_us();
mjr 82:4f6209cb5c33 432
mjr 82:4f6209cb5c33 433 // start the next integration cycle by pulsing SI and one clock
mjr 82:4f6209cb5c33 434 si = 1;
mjr 82:4f6209cb5c33 435 clock = 1;
mjr 82:4f6209cb5c33 436 si = 0;
mjr 82:4f6209cb5c33 437 clock = 0;
mjr 82:4f6209cb5c33 438
mjr 82:4f6209cb5c33 439 // Set the timestamp for the current active buffer. The SI pulse
mjr 86:e30a1f60f783 440 // we just did performed the HOLD operation, which takes a snapshot
mjr 86:e30a1f60f783 441 // of the photo receptors and stores it in the sensor's shift
mjr 86:e30a1f60f783 442 // register. We noted the start of the current integration cycle
mjr 86:e30a1f60f783 443 // in tInt when we started it during the previous scan. The image
mjr 86:e30a1f60f783 444 // we're about to transfer therefore represents the light collected
mjr 86:e30a1f60f783 445 // between tInt and right now (actually, the SI pulse above, but
mjr 86:e30a1f60f783 446 // close enough). The image covers a time range rather than a
mjr 86:e30a1f60f783 447 // single point in time, but we still have to give it a single
mjr 86:e30a1f60f783 448 // timestamp. Use the midpoint of the integration period.
mjr 82:4f6209cb5c33 449 uint32_t tmid = (t0 + tInt) >> 1;
mjr 82:4f6209cb5c33 450 if (pixDMA)
mjr 82:4f6209cb5c33 451 t2 = tmid;
mjr 82:4f6209cb5c33 452 else
mjr 82:4f6209cb5c33 453 t1 = tmid;
mjr 82:4f6209cb5c33 454
mjr 82:4f6209cb5c33 455 // Start the ADC sampler. The ADC will read samples continuously
mjr 82:4f6209cb5c33 456 // until we tell it to stop. Each sample completion will trigger
mjr 82:4f6209cb5c33 457 // our linked DMA channel, which will store the next sample in our
mjr 82:4f6209cb5c33 458 // pixel array and pulse the CCD serial data clock to load the next
mjr 82:4f6209cb5c33 459 // pixel onto the analog sampler pin. This will all happen without
mjr 82:4f6209cb5c33 460 // any CPU involvement, so we can continue with other work.
mjr 82:4f6209cb5c33 461 ao.start();
mjr 82:4f6209cb5c33 462
mjr 82:4f6209cb5c33 463 // The new integration cycle starts with the 19th clock pulse
mjr 82:4f6209cb5c33 464 // after the SI pulse. We offload all of the transfer work (including
mjr 86:e30a1f60f783 465 // the clock pulse generation) to the DMA controller, which doesn't
mjr 86:e30a1f60f783 466 // notify when that 19th pulse occurs, so we have to approximate.
mjr 86:e30a1f60f783 467 // Based on empirical measurements, each pixel transfer in our DMA
mjr 86:e30a1f60f783 468 // setup takes about 2us, so clocking 19 pixels takes about 38us.
mjr 86:e30a1f60f783 469 // In addition, the ADC takes about 4us extra for the first read.
mjr 86:e30a1f60f783 470 tInt = t.read_us() + 19*2 + 4;
mjr 82:4f6209cb5c33 471
mjr 82:4f6209cb5c33 472 IF_DIAG(mainLoopIterCheckpt[9] += uint32_t(mainLoopTimer.read_us() - tDiag0);)
mjr 82:4f6209cb5c33 473 }
mjr 82:4f6209cb5c33 474
mjr 82:4f6209cb5c33 475 // Wait for the current capture to finish
mjr 82:4f6209cb5c33 476 void wait()
mjr 82:4f6209cb5c33 477 {
mjr 82:4f6209cb5c33 478 while (running) { }
mjr 82:4f6209cb5c33 479 }
mjr 82:4f6209cb5c33 480
mjr 86:e30a1f60f783 481 // Is the latest reading ready?
mjr 82:4f6209cb5c33 482 bool ready() const { return !running; }
mjr 82:4f6209cb5c33 483
mjr 82:4f6209cb5c33 484 // Clock through all pixels to clear the array. Pulses SI at the
mjr 82:4f6209cb5c33 485 // beginning of the operation, which starts a new integration cycle.
mjr 82:4f6209cb5c33 486 void clear()
mjr 82:4f6209cb5c33 487 {
mjr 82:4f6209cb5c33 488 // get the clock toggle register
mjr 82:4f6209cb5c33 489 volatile uint32_t *ptor = &clockPort->PTOR;
mjr 82:4f6209cb5c33 490
mjr 82:4f6209cb5c33 491 // make sure any DMA run is completed
mjr 82:4f6209cb5c33 492 wait();
mjr 82:4f6209cb5c33 493
mjr 82:4f6209cb5c33 494 // clock in an SI pulse
mjr 82:4f6209cb5c33 495 si = 1;
mjr 82:4f6209cb5c33 496 *ptor = clockMask;
mjr 82:4f6209cb5c33 497 clockPort->PSOR = clockMask;
mjr 82:4f6209cb5c33 498 si = 0;
mjr 82:4f6209cb5c33 499 *ptor = clockMask;
mjr 82:4f6209cb5c33 500
mjr 82:4f6209cb5c33 501 // This starts a new integration period. Or more precisely, the
mjr 82:4f6209cb5c33 502 // 19th clock pulse will start the new integration period. We're
mjr 82:4f6209cb5c33 503 // going to blast the clock signal as fast as we can, at about
mjr 82:4f6209cb5c33 504 // 100ns intervals (50ns up and 50ns down), so the 19th clock
mjr 82:4f6209cb5c33 505 // will be about 2us from now.
mjr 82:4f6209cb5c33 506 tInt = t.read_us() + 2;
mjr 82:4f6209cb5c33 507
mjr 82:4f6209cb5c33 508 // clock out all pixels, plus an extra one to clock past the last
mjr 82:4f6209cb5c33 509 // pixel and reset the last pixel's internal sampling switch in
mjr 82:4f6209cb5c33 510 // the sensor
mjr 82:4f6209cb5c33 511 for (int i = 0 ; i < nPixSensor + 1 ; )
mjr 82:4f6209cb5c33 512 {
mjr 82:4f6209cb5c33 513 // toggle the clock to take it high
mjr 82:4f6209cb5c33 514 *ptor = clockMask;
mjr 82:4f6209cb5c33 515
mjr 82:4f6209cb5c33 516 // increment our loop variable here to pad the timing, to
mjr 82:4f6209cb5c33 517 // keep our pulse width long enough for the sensor
mjr 82:4f6209cb5c33 518 ++i;
mjr 82:4f6209cb5c33 519
mjr 82:4f6209cb5c33 520 // toggle the clock to take it low
mjr 82:4f6209cb5c33 521 *ptor = clockMask;
mjr 82:4f6209cb5c33 522 }
mjr 82:4f6209cb5c33 523 }
mjr 82:4f6209cb5c33 524
mjr 82:4f6209cb5c33 525 // get the timing statistics - sum of scan time for all scans so far
mjr 82:4f6209cb5c33 526 // in microseconds, and total number of scans so far
mjr 82:4f6209cb5c33 527 void getTimingStats(uint64_t &totalTime, uint32_t &nRuns) const
mjr 82:4f6209cb5c33 528 {
mjr 82:4f6209cb5c33 529 totalTime = this->totalTime;
mjr 82:4f6209cb5c33 530 nRuns = this->nRuns;
mjr 82:4f6209cb5c33 531 }
mjr 82:4f6209cb5c33 532
mjr 82:4f6209cb5c33 533 // get the average scan time in microseconds
mjr 82:4f6209cb5c33 534 uint32_t getAvgScanTime() const
mjr 82:4f6209cb5c33 535 {
mjr 82:4f6209cb5c33 536 return uint32_t(totalTime / nRuns);
mjr 82:4f6209cb5c33 537 }
mjr 82:4f6209cb5c33 538
mjr 82:4f6209cb5c33 539 private:
mjr 82:4f6209cb5c33 540 // end of transfer notification
mjr 82:4f6209cb5c33 541 void transferDone()
mjr 82:4f6209cb5c33 542 {
mjr 82:4f6209cb5c33 543 // stop the ADC sampler
mjr 82:4f6209cb5c33 544 ao.stop();
mjr 82:4f6209cb5c33 545
mjr 82:4f6209cb5c33 546 // clock out one extra pixel to leave A1 in the high-Z state
mjr 82:4f6209cb5c33 547 clock = 1;
mjr 82:4f6209cb5c33 548 clock = 0;
mjr 86:e30a1f60f783 549
mjr 86:e30a1f60f783 550 // add this sample to the timing statistics (for diagnostics and
mjr 86:e30a1f60f783 551 // performance measurement)
mjr 86:e30a1f60f783 552 uint32_t now = t.read_us();
mjr 86:e30a1f60f783 553 totalTime += uint32_t(now - t0);
mjr 82:4f6209cb5c33 554 nRuns += 1;
mjr 82:4f6209cb5c33 555
mjr 82:4f6209cb5c33 556 // the sampler is no long running
mjr 82:4f6209cb5c33 557 running = false;
mjr 86:e30a1f60f783 558
mjr 86:e30a1f60f783 559 // note the ending time of the transfer
mjr 86:e30a1f60f783 560 tDone = now;
mjr 82:4f6209cb5c33 561 }
mjr 82:4f6209cb5c33 562
mjr 82:4f6209cb5c33 563 // DMA controller interfaces
mjr 82:4f6209cb5c33 564 SimpleDMA adc_dma; // DMA channel for reading the analog input
mjr 82:4f6209cb5c33 565 SimpleDMA clkUp_dma; // "Clock Up" channel
mjr 82:4f6209cb5c33 566 SimpleDMA clkDn_dma; // "Clock Down" channel
mjr 82:4f6209cb5c33 567
mjr 82:4f6209cb5c33 568 // Sensor interface pins
mjr 82:4f6209cb5c33 569 DigitalOut si; // GPIO pin for sensor SI (serial data)
mjr 82:4f6209cb5c33 570 DigitalOut clock; // GPIO pin for sensor SCLK (serial clock)
mjr 82:4f6209cb5c33 571 GPIO_Type *clockPort; // IOPORT base address for clock pin - cached for DMA writes
mjr 82:4f6209cb5c33 572 uint32_t clockMask; // IOPORT register bit mask for clock pin
mjr 82:4f6209cb5c33 573 AltAnalogIn ao; // GPIO pin for sensor AO (analog output)
mjr 82:4f6209cb5c33 574
mjr 82:4f6209cb5c33 575 // number of pixels in the physical sensor array
mjr 82:4f6209cb5c33 576 int nPixSensor; // number of pixels in physical sensor array
mjr 82:4f6209cb5c33 577
mjr 82:4f6209cb5c33 578 // pixel buffers - we keep two buffers so that we can transfer the
mjr 82:4f6209cb5c33 579 // current sensor data into one buffer via DMA while we concurrently
mjr 82:4f6209cb5c33 580 // process the last buffer
mjr 82:4f6209cb5c33 581 uint8_t *pix1; // pixel array 1
mjr 82:4f6209cb5c33 582 uint8_t *pix2; // pixel array 2
mjr 82:4f6209cb5c33 583
mjr 82:4f6209cb5c33 584 // Timestamps of pix1 and pix2 arrays, in microseconds, in terms of the
mjr 82:4f6209cb5c33 585 // ample timer (this->t).
mjr 82:4f6209cb5c33 586 uint32_t t1;
mjr 82:4f6209cb5c33 587 uint32_t t2;
mjr 82:4f6209cb5c33 588
mjr 82:4f6209cb5c33 589 // DMA target buffer. This is the buffer for the next DMA transfer.
mjr 82:4f6209cb5c33 590 // 0 means pix1, 1 means pix2. The other buffer contains the stable
mjr 82:4f6209cb5c33 591 // data from the last transfer.
mjr 82:4f6209cb5c33 592 uint8_t pixDMA;
mjr 82:4f6209cb5c33 593
mjr 82:4f6209cb5c33 594 // flag: sample is running
mjr 82:4f6209cb5c33 595 volatile bool running;
mjr 82:4f6209cb5c33 596
mjr 82:4f6209cb5c33 597 // timing statistics
mjr 82:4f6209cb5c33 598 Timer t; // sample timer
mjr 82:4f6209cb5c33 599 uint32_t t0; // start time (us) of current sample
mjr 82:4f6209cb5c33 600 uint32_t tInt; // start time (us) of current integration period
mjr 86:e30a1f60f783 601 uint32_t tDone; // end time of latest finished transfer
mjr 82:4f6209cb5c33 602 uint64_t totalTime; // total time consumed by all reads so far
mjr 82:4f6209cb5c33 603 uint32_t nRuns; // number of runs so far
mjr 82:4f6209cb5c33 604 };
mjr 82:4f6209cb5c33 605
mjr 82:4f6209cb5c33 606 #endif /* TSL14XX_H */