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


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 Also visit my Pinscape Resources page for more about this project and other virtual pinball projects I'm working on.


  • 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.


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 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 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.

Sat Apr 18 19:08:55 2020 +0000
TCD1103 DMA setup time padding to fix sporadic missed first pixel in transfer; fix TV ON so that the TV ON IR commands don't have to be grouped in the IR command first slots

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mjr 82:4f6209cb5c33 1 // AEDR-8300-1K2 optical encoder / generic quadrature sensor plunger
mjr 82:4f6209cb5c33 2 // implementation
mjr 82:4f6209cb5c33 3 //
mjr 82:4f6209cb5c33 4 // This class implements the Pinscape plunger interface for the
mjr 82:4f6209cb5c33 5 // AEDR-8300-1K2 optical encoder in particular, and quadrature sensors
mjr 82:4f6209cb5c33 6 // in general. The code was written specifically for the AEDR-8300-1K2,
mjr 82:4f6209cb5c33 7 // but it should work with any other quadrature sensor that's electrically
mjr 82:4f6209cb5c33 8 // compatible and that doesn't exceed the maximum interrupt rate we can
mjr 82:4f6209cb5c33 9 // handle on the KL25Z. To be electrically compatible, the device must
mjr 82:4f6209cb5c33 10 // be 3.3V compatible, have logic type outputs (basically square waves
mjr 82:4f6209cb5c33 11 // for the signals), and provide two outputs 90 degrees out of phase.
mjr 82:4f6209cb5c33 12 // The maximum interrupt rate that the KL25Z can handle (with our
mjr 82:4f6209cb5c33 13 // FastInterruptIn class) is about 150 kHz.
mjr 82:4f6209cb5c33 14 //
mjr 82:4f6209cb5c33 15 // A quadrature sensor works by detecting transitions along a bar-coded
mjr 82:4f6209cb5c33 16 // scale. Most position encoders (including the AEDR-8300) are optical,
mjr 82:4f6209cb5c33 17 // but the same principle can be used with other technologies, such as
mjr 82:4f6209cb5c33 18 // magnetic pole strips. Whatever the underlying physical "bar" type,
mjr 82:4f6209cb5c33 19 // the device detects transitions between the bars and the spaces between
mjr 82:4f6209cb5c33 20 // the bars and relays them to the microcontroller via its outputs. A
mjr 82:4f6209cb5c33 21 // quadrature device actually consists of two such sensors, slightly offset
mjr 82:4f6209cb5c33 22 // from each other relative to the direction of motion of the scale, so
mjr 82:4f6209cb5c33 23 // that their bar transitions are 90 degrees out of phase. The phase
mjr 82:4f6209cb5c33 24 // shift in the two signals is what allows the microcontroller to sense
mjr 82:4f6209cb5c33 25 // the direction of motion. The controller figures the current position
mjr 82:4f6209cb5c33 26 // by counting bar transitions (incrementing the count when moving in one
mjr 82:4f6209cb5c33 27 // direction and decrement it in the other direction), so it knows the
mjr 82:4f6209cb5c33 28 // location at any given time as an offset in units of bar widths from the
mjr 82:4f6209cb5c33 29 // starting position. The position reading is always relative, because
mjr 82:4f6209cb5c33 30 // we can only count up or down from the initial point.
mjr 82:4f6209cb5c33 31 //
mjr 82:4f6209cb5c33 32 // In many applications involving quadrature sensors, the relative
mjr 82:4f6209cb5c33 33 // quadrature reading is augmented with a separate sensor for absolute
mjr 82:4f6209cb5c33 34 // positioning. This is usually something simple and low-res, like an
mjr 82:4f6209cb5c33 35 // end-of-stroke switch or a zero-crossing switch. The idea is that you
mjr 82:4f6209cb5c33 36 // use the low-res absolute sensor to tell when you're at a known reference
mjr 82:4f6209cb5c33 37 // point, and then use the high-res quadrature data to get the precise
mjr 82:4f6209cb5c33 38 // location relative to the reference point. To keep things simple, we
mjr 82:4f6209cb5c33 39 // don't use any such supplemental absolute sensor. It's not really
mjr 82:4f6209cb5c33 40 // necessary for a plunger, because a plunger has the special property
mjr 82:4f6209cb5c33 41 // that it always returns to the same point when not being manipulated.
mjr 82:4f6209cb5c33 42 // It's almost as good as having a sensor at the park position, because
mjr 82:4f6209cb5c33 43 // even though we can't know for sure the plunger is there at any given
mjr 82:4f6209cb5c33 44 // time, it's a good bet that that's where it is at startup and any time
mjr 82:4f6209cb5c33 45 // we haven't seen any motion in a while. Note that we could easily add
mjr 82:4f6209cb5c33 46 // support in the software for some kind of absolute sensing if it became
mjr 82:4f6209cb5c33 47 // desirable; the only challenge is the complexity it would add to the
mjr 82:4f6209cb5c33 48 // physical system.
mjr 82:4f6209cb5c33 49 //
mjr 82:4f6209cb5c33 50 // The AEDR-8300 lets us collect some very precise data on the
mjr 82:4f6209cb5c33 51 // instantaneous speed of the plunger thanks to its high resolution and
mjr 82:4f6209cb5c33 52 // real-time position updates. The shortest observed time between pulses
mjr 82:4f6209cb5c33 53 // (so far, with my test rig) is 19us. Pulses are generated at 4 per
mjr 82:4f6209cb5c33 54 // bar, with bars at 75 per inch, yielding 300 pulses per inch. The 19us
mjr 82:4f6209cb5c33 55 // pulse time translates to an instantaneous plunger speed of 0.175
mjr 82:4f6209cb5c33 56 // inches/millisecond, or 4.46 mm/ms, or 4.46 m/s, or 9.97 mph.
mjr 82:4f6209cb5c33 57 //
mjr 82:4f6209cb5c33 58 // The peak interrupt rate of 19us is well within the KL25Z's comfort
mjr 82:4f6209cb5c33 59 // zone, as long as we take reasonable measures to minimize latency. In
mjr 82:4f6209cb5c33 60 // particular, we have to elevate the GPIO port IRQ priority above all
mjr 82:4f6209cb5c33 61 // other hardware interrupts. That's vital because there are some
mjr 82:4f6209cb5c33 62 // relatively long-running interrupt handlers in the system, particularly
mjr 82:4f6209cb5c33 63 // the USB handlers and the microsecond timer. It's also vital to keep
mjr 82:4f6209cb5c33 64 // other GPIO interrupt handlers very fast, since the ports all share
mjr 82:4f6209cb5c33 65 // a priority level and thus can't preempt one another. Fortunately, the
mjr 82:4f6209cb5c33 66 // rest of the Pinscape system make very little use of GPIO interrupts;
mjr 82:4f6209cb5c33 67 // the only current use is in the IR receiver, and that code is designed
mjr 82:4f6209cb5c33 68 // to do minimal work in IRQ context.
mjr 82:4f6209cb5c33 69 //
mjr 82:4f6209cb5c33 70 // We use our custom FastInterruptIn class instead of the original mbed
mjr 82:4f6209cb5c33 71 // InterruptIn. FastInterruptIn gives us a modest speed improvement: it
mjr 82:4f6209cb5c33 72 // has a measured overhead time per interrupt of about 6.5us compared with
mjr 82:4f6209cb5c33 73 // the mbed libary's 8.9us, which gives us a maximum interrupt rate of
mjr 82:4f6209cb5c33 74 // about 159kHz vs mbed's 112kHz. The AEDR-8300's maximum 19us is well
mjr 82:4f6209cb5c33 75 // within both limits, but FastInterruptIn gives us a little more headroom
mjr 82:4f6209cb5c33 76 // for substituting other sensors with higher pulse rates.
mjr 82:4f6209cb5c33 77 //
mjr 82:4f6209cb5c33 78
mjr 82:4f6209cb5c33 79 #ifndef _QUADSENSOR_H_
mjr 82:4f6209cb5c33 80 #define _QUADSENSOR_H_
mjr 82:4f6209cb5c33 81
mjr 82:4f6209cb5c33 82 #include "FastInterruptIn.h"
mjr 82:4f6209cb5c33 83
mjr 82:4f6209cb5c33 84 class PlungerSensorQuad: public PlungerSensor
mjr 82:4f6209cb5c33 85 {
mjr 82:4f6209cb5c33 86 public:
mjr 82:4f6209cb5c33 87 // Construct.
mjr 82:4f6209cb5c33 88 //
mjr 82:4f6209cb5c33 89 // 'dpi' is the approximate number of dots per inch of linear travel
mjr 82:4f6209cb5c33 90 // that the sensor can distinguish. This is equivalent to the number
mjr 82:4f6209cb5c33 91 // of pulses it generates per inch. This doesn't have to be exact,
mjr 82:4f6209cb5c33 92 // since the main loop rescales it anyway via calibration. But it's
mjr 82:4f6209cb5c33 93 // helpful to have the approximate figure so that we can scale the
mjr 82:4f6209cb5c33 94 // raw data readings appropriately for the interface datatypes.
mjr 86:e30a1f60f783 95 //
mjr 86:e30a1f60f783 96 // For the native scale, we'll assume a 4" range at our dpi rating.
mjr 86:e30a1f60f783 97 // The actual plunger travel is constrainted to about a 3" range, but
mjr 86:e30a1f60f783 98 // we want to leave a little extra padding to reduce the chances of
mjr 86:e30a1f60f783 99 // going out of range in unusual situations.
mjr 82:4f6209cb5c33 100 PlungerSensorQuad(int dpi, PinName pinA, PinName pinB)
mjr 86:e30a1f60f783 101 : PlungerSensor(dpi*4),
mjr 86:e30a1f60f783 102 chA(pinA), chB(pinB)
mjr 82:4f6209cb5c33 103 {
mjr 82:4f6209cb5c33 104 // Use 1" as the reference park position
mjr 82:4f6209cb5c33 105 parkPos = dpi;
mjr 82:4f6209cb5c33 106
mjr 82:4f6209cb5c33 107 // start at the park position
mjr 82:4f6209cb5c33 108 pos = parkPos;
mjr 82:4f6209cb5c33 109
mjr 82:4f6209cb5c33 110 // get the initial pin states
mjr 82:4f6209cb5c33 111 st = ( ? 0x01 : 0x00)
mjr 82:4f6209cb5c33 112 | ( ? 0x02 : 0x00);
mjr 82:4f6209cb5c33 113
mjr 82:4f6209cb5c33 114 // set up the interrupt handlers
mjr 82:4f6209cb5c33 115 chA.rise(&PlungerSensorQuad::aUp, this);
mjr 82:4f6209cb5c33 116 chA.fall(&PlungerSensorQuad::aDown, this);
mjr 82:4f6209cb5c33 117 chB.rise(&PlungerSensorQuad::bUp, this);
mjr 82:4f6209cb5c33 118 chB.fall(&PlungerSensorQuad::bDown, this);
mjr 82:4f6209cb5c33 119
mjr 82:4f6209cb5c33 120 // start our sample timer with an arbitrary zero point of now
mjr 82:4f6209cb5c33 121 timer.start();
mjr 82:4f6209cb5c33 122 }
mjr 82:4f6209cb5c33 123
mjr 105:6a25bbfae1e4 124 // Auto-zero. Return to the park position. If we're using reverse
mjr 105:6a25bbfae1e4 125 // orientation, go to the park position distance from the top end
mjr 105:6a25bbfae1e4 126 // of the scale.
mjr 82:4f6209cb5c33 127 virtual void autoZero()
mjr 82:4f6209cb5c33 128 {
mjr 105:6a25bbfae1e4 129 pos = reverseOrientation ? nativeScale - parkPos : parkPos;
mjr 82:4f6209cb5c33 130 }
mjr 82:4f6209cb5c33 131
mjr 82:4f6209cb5c33 132 // Begin calibration. We can assume that the plunger is at the
mjr 105:6a25bbfae1e4 133 // park position when calibration starts, so perform an explicit
mjr 105:6a25bbfae1e4 134 // auto-zeroing operation.
mjr 100:1ff35c07217c 135 virtual void beginCalibration(Config &)
mjr 82:4f6209cb5c33 136 {
mjr 105:6a25bbfae1e4 137 autoZero();
mjr 82:4f6209cb5c33 138 }
mjr 82:4f6209cb5c33 139
mjr 82:4f6209cb5c33 140 // read the sensor
mjr 86:e30a1f60f783 141 virtual bool readRaw(PlungerReading &r)
mjr 82:4f6209cb5c33 142 {
mjr 86:e30a1f60f783 143 // Get the current position in native units
mjr 86:e30a1f60f783 144 r.pos = pos;
mjr 82:4f6209cb5c33 145
mjr 82:4f6209cb5c33 146 // Set the timestamp on the reading to right now. Our internal
mjr 82:4f6209cb5c33 147 // position counter reflects the position in real time, since it's
mjr 82:4f6209cb5c33 148 // updated in the interrupt handlers for the change signals from
mjr 82:4f6209cb5c33 149 // the sensor.
mjr 82:4f6209cb5c33 150 r.t = timer.read_us();
mjr 82:4f6209cb5c33 151
mjr 82:4f6209cb5c33 152 // success
mjr 82:4f6209cb5c33 153 return true;
mjr 82:4f6209cb5c33 154 }
mjr 82:4f6209cb5c33 155
mjr 108:bd5d4bd4383b 156 virtual void sendStatusReport(class USBJoystick &js, uint8_t flags)
mjr 108:bd5d4bd4383b 157 {
mjr 108:bd5d4bd4383b 158 // send the common status report
mjr 108:bd5d4bd4383b 159 PlungerSensor::sendStatusReport(js, flags);
mjr 108:bd5d4bd4383b 160
mjr 108:bd5d4bd4383b 161 // send the extra quadrature sensor status report
mjr 108:bd5d4bd4383b 162 js.sendPlungerStatusQuadrature((st & 0x01) != 0, (st & 0x02) != 0);
mjr 108:bd5d4bd4383b 163 }
mjr 108:bd5d4bd4383b 164
mjr 82:4f6209cb5c33 165 // figure the average scan time in microseconds
mjr 82:4f6209cb5c33 166 virtual uint32_t getAvgScanTime()
mjr 82:4f6209cb5c33 167 {
mjr 82:4f6209cb5c33 168 // we're updated by interrupts rather than scanning, so our
mjr 82:4f6209cb5c33 169 // "scan time" is exactly zero
mjr 82:4f6209cb5c33 170 return 0;
mjr 82:4f6209cb5c33 171 }
mjr 101:755f44622abc 172
mjr 82:4f6209cb5c33 173 private:
mjr 82:4f6209cb5c33 174 // interrupt inputs for our channel pins
mjr 82:4f6209cb5c33 175 FastInterruptIn chA, chB;
mjr 82:4f6209cb5c33 176
mjr 82:4f6209cb5c33 177 // current position - this is the cumulate counter for all
mjr 82:4f6209cb5c33 178 // transitions so far
mjr 82:4f6209cb5c33 179 int pos;
mjr 82:4f6209cb5c33 180
mjr 82:4f6209cb5c33 181 // Park position. This is essentially arbitrary, since our readings
mjr 82:4f6209cb5c33 182 // are entirely relative, but for interface purposes we have to keep
mjr 82:4f6209cb5c33 183 // our raw readings positive. We need an initial park position that's
mjr 82:4f6209cb5c33 184 // non-zero so that plunger motion forward of the park position remains
mjr 82:4f6209cb5c33 185 // positive.
mjr 82:4f6209cb5c33 186 int parkPos;
mjr 82:4f6209cb5c33 187
mjr 82:4f6209cb5c33 188 // Channel state on last read. This is a bit vector combining
mjr 82:4f6209cb5c33 189 // the two channel states:
mjr 82:4f6209cb5c33 190 // 0x01 = channel A state
mjr 82:4f6209cb5c33 191 // 0x02 = channel B state
mjr 82:4f6209cb5c33 192 uint8_t st;
mjr 82:4f6209cb5c33 193
mjr 82:4f6209cb5c33 194 // interrupt handlers
mjr 82:4f6209cb5c33 195 static void aUp(void *obj) {
mjr 82:4f6209cb5c33 196 PlungerSensorQuad *self = (PlungerSensorQuad *)obj;
mjr 82:4f6209cb5c33 197 self->transition(self->st | 0x01);
mjr 82:4f6209cb5c33 198 }
mjr 82:4f6209cb5c33 199 static void aDown(void *obj) {
mjr 82:4f6209cb5c33 200 PlungerSensorQuad *self = (PlungerSensorQuad *)obj;
mjr 82:4f6209cb5c33 201 self->transition(self->st & 0x02);
mjr 82:4f6209cb5c33 202 }
mjr 82:4f6209cb5c33 203 static void bUp(void *obj) {
mjr 82:4f6209cb5c33 204 PlungerSensorQuad *self = (PlungerSensorQuad *)obj;
mjr 82:4f6209cb5c33 205 self->transition(self->st | 0x02);
mjr 82:4f6209cb5c33 206 }
mjr 82:4f6209cb5c33 207 static void bDown(void *obj) {
mjr 82:4f6209cb5c33 208 PlungerSensorQuad *self = (PlungerSensorQuad *)obj;
mjr 82:4f6209cb5c33 209 self->transition(self->st & 0x01);
mjr 82:4f6209cb5c33 210 }
mjr 82:4f6209cb5c33 211
mjr 82:4f6209cb5c33 212 // Transition handler. The interrupt handlers call this, so
mjr 82:4f6209cb5c33 213 // it's critical that this run as fast as possible. The observed
mjr 82:4f6209cb5c33 214 // peak interrupt rate is one interrupt per 19us. Fortunately,
mjr 82:4f6209cb5c33 215 // our work here is simple: we just have to count the pulse in
mjr 82:4f6209cb5c33 216 // the appropriate direction according to the state transition
mjr 82:4f6209cb5c33 217 // that the pulse represents. We can do this with a simple table
mjr 82:4f6209cb5c33 218 // lookup.
mjr 82:4f6209cb5c33 219 inline void transition(int stNew)
mjr 82:4f6209cb5c33 220 {
mjr 108:bd5d4bd4383b 221 // Transition matrix: dir[n][m] gives the direction of
mjr 108:bd5d4bd4383b 222 // motion when we switch from state 'n' to state 'm'.
mjr 82:4f6209cb5c33 223 // The state number is formed by the two-bit number B:A,
mjr 82:4f6209cb5c33 224 // where each bit is 1 if the channel pulse is on and 0
mjr 82:4f6209cb5c33 225 // if the channel pulse is off. E.g., if chA is OFF and
mjr 82:4f6209cb5c33 226 // chB is ON, B:A = 1:0, so the state number is 0b10 = 2.
mjr 82:4f6209cb5c33 227 // Slots with 'NV' are Not Valid: it's impossible to make
mjr 82:4f6209cb5c33 228 // this transition (unless we missed an interrupt). 'NC'
mjr 82:4f6209cb5c33 229 // means No Change; these are the slots on the matrix
mjr 82:4f6209cb5c33 230 // diagonal, which represent the same state on both input
mjr 82:4f6209cb5c33 231 // and output. Like NV transitions, NC transitions should
mjr 82:4f6209cb5c33 232 // never happen, in this case because no interrupt should
mjr 82:4f6209cb5c33 233 // be generated when nothing has changed.
mjr 82:4f6209cb5c33 234 const int NV = 0, NC = 0;
mjr 82:4f6209cb5c33 235 static const int dir[][4] = {
mjr 82:4f6209cb5c33 236 { NC, 1, -1, NV },
mjr 82:4f6209cb5c33 237 { -1, NC, NV, 1 },
mjr 82:4f6209cb5c33 238 { 1, NV, NC, -1 },
mjr 82:4f6209cb5c33 239 { NV, -1, 1, NC }
mjr 82:4f6209cb5c33 240 };
mjr 82:4f6209cb5c33 241
mjr 82:4f6209cb5c33 242 // increment or decrement the position counter by one notch,
mjr 82:4f6209cb5c33 243 // according to the direction of motion implied by the transition
mjr 82:4f6209cb5c33 244 pos += dir[st][stNew];
mjr 82:4f6209cb5c33 245
mjr 82:4f6209cb5c33 246 // the new state is now the current state
mjr 82:4f6209cb5c33 247 st = stNew;
mjr 82:4f6209cb5c33 248 }
mjr 82:4f6209cb5c33 249
mjr 82:4f6209cb5c33 250 // timer for input timestamps
mjr 82:4f6209cb5c33 251 Timer timer;
mjr 82:4f6209cb5c33 252 };
mjr 82:4f6209cb5c33 253
mjr 82:4f6209cb5c33 254 #endif