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.

Thu Feb 18 07:32:20 2016 +0000
3-channel linked DMA scheme for CCD image capture working

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mjr 26:cb71c4af2912 1 // Pinscape Controller TLC5940 interface
mjr 26:cb71c4af2912 2 //
mjr 26:cb71c4af2912 3 // Based on Spencer Davis's mbed TLC5940 library. Adapted for the
mjr 26:cb71c4af2912 4 // KL25Z, and simplified to just the functions needed for this
mjr 26:cb71c4af2912 5 // application. In particular, this version doesn't include support
mjr 26:cb71c4af2912 6 // for dot correction programming or status input. This version also
mjr 26:cb71c4af2912 7 // uses a different approach for sending the grayscale data updates,
mjr 26:cb71c4af2912 8 // sending updates during the blanking interval rather than overlapping
mjr 26:cb71c4af2912 9 // them with the PWM cycle. This results in very slightly longer
mjr 26:cb71c4af2912 10 // blanking intervals when updates are pending, effectively reducing
mjr 26:cb71c4af2912 11 // the PWM "on" duty cycle (and thus the output brightness) by about
mjr 26:cb71c4af2912 12 // 0.3%. This shouldn't be perceptible to users, so it's a small
mjr 26:cb71c4af2912 13 // trade-off for the advantage gained, which is much better signal
mjr 26:cb71c4af2912 14 // stability when using multiple TLC5940s daisy-chained together.
mjr 26:cb71c4af2912 15 // I saw a lot of instability when using the overlapped approach,
mjr 26:cb71c4af2912 16 // which seems to be eliminated entirely when sending updates during
mjr 26:cb71c4af2912 17 // the blanking interval.
mjr 26:cb71c4af2912 18
mjr 26:cb71c4af2912 19
mjr 26:cb71c4af2912 20 #ifndef TLC5940_H
mjr 26:cb71c4af2912 21 #define TLC5940_H
mjr 26:cb71c4af2912 22
mjr 38:091e511ce8a0 23 // Data Transmission Mode.
mjr 38:091e511ce8a0 24 //
mjr 38:091e511ce8a0 25 // NOTE! This section contains a possible workaround to try if you're
mjr 38:091e511ce8a0 26 // having data signal stability problems with your TLC5940 chips. If
mjr 40:cc0d9814522b 27 // things are working properly, you can ignore this part.
mjr 33:d832bcab089e 28 //
mjr 38:091e511ce8a0 29 // The software has two options for sending data updates to the chips:
mjr 38:091e511ce8a0 30 //
mjr 40:cc0d9814522b 31 // Mode 0: Send data *during* the grayscale cycle. This is the default,
mjr 40:cc0d9814522b 32 // and it's the standard method the chips are designed for. In this mode,
mjr 40:cc0d9814522b 33 // we start sending an update just after then blanking interval that starts
mjr 40:cc0d9814522b 34 // a new grayscale cycle. The timing is arranged so that the update is
mjr 40:cc0d9814522b 35 // completed well before the end of the grayscale cycle. At the next
mjr 40:cc0d9814522b 36 // blanking interval, we latch the new data, so the new brightness levels
mjr 40:cc0d9814522b 37 // will be shown starting on the next cycle.
mjr 40:cc0d9814522b 38
mjr 38:091e511ce8a0 39 // Mode 1: Send data *between* grayscale cycles. In this mode, we send
mjr 38:091e511ce8a0 40 // each complete update during a blanking period, then latch the update
mjr 38:091e511ce8a0 41 // and start the next grayscale cycle. This isn't the way the chips were
mjr 38:091e511ce8a0 42 // intended to be used, but it works. The disadvantage is that it requires
mjr 40:cc0d9814522b 43 // the blanking interval to be extended long enough for the full data
mjr 40:cc0d9814522b 44 // update (192 bits * the number of chips in the chain). Since the
mjr 40:cc0d9814522b 45 // outputs are turned off throughout the blanking period, this reduces
mjr 38:091e511ce8a0 46 // the overall brightness/intensity of the outputs by reducing the duty
mjr 38:091e511ce8a0 47 // cycle. The TLC5940 chips can't achieve 100% duty cycle to begin with,
mjr 40:cc0d9814522b 48 // since they require a brief minimum time in the blanking interval
mjr 38:091e511ce8a0 49 // between grayscale cycles; however, the minimum is so short that the
mjr 38:091e511ce8a0 50 // duty cycle is close to 100%. With the full data transmission stuffed
mjr 38:091e511ce8a0 51 // into the blanking interval, we reduce the duty cycle further below
mjr 38:091e511ce8a0 52 // 100%. With four chips in the chain, a 28 MHz data clock, and a
mjr 38:091e511ce8a0 53 // 500 kHz grayscale clock, the reduction is about 0.3%.
mjr 33:d832bcab089e 54 //
mjr 40:cc0d9814522b 55 // Mode 0 is the method documented in the manufacturer's data sheet.
mjr 40:cc0d9814522b 56 // It works well empirically with the Pinscape expansion boards.
mjr 40:cc0d9814522b 57 //
mjr 38:091e511ce8a0 58 // So what's the point of Mode 1? In early testing, with a breadboard
mjr 38:091e511ce8a0 59 // setup, I saw some problems with data signal stability, which manifested
mjr 38:091e511ce8a0 60 // as sporadic flickering in the outputs. Switching to Mode 1 improved
mjr 38:091e511ce8a0 61 // the signal stability considerably. I'm therefore leaving this code
mjr 38:091e511ce8a0 62 // available as an option in case anyone runs into similar signal problems
mjr 38:091e511ce8a0 63 // and wants to try the alternative mode as a workaround.
mjr 38:091e511ce8a0 64 //
mjr 38:091e511ce8a0 65 #define DATA_UPDATE_INSIDE_BLANKING 0
mjr 33:d832bcab089e 66
mjr 26:cb71c4af2912 67 #include "mbed.h"
mjr 26:cb71c4af2912 68 #include "FastPWM.h"
mjr 30:6e9902f06f48 69 #include "SimpleDMA.h"
mjr 47:df7a88cd249c 70 #include "DMAChannels.h"
mjr 26:cb71c4af2912 71
mjr 26:cb71c4af2912 72 /**
mjr 26:cb71c4af2912 73 * SPI speed used by the mbed to communicate with the TLC5940
mjr 26:cb71c4af2912 74 * The TLC5940 supports up to 30Mhz. It's best to keep this as
mjr 33:d832bcab089e 75 * high as possible, since a higher SPI speed yields a faster
mjr 33:d832bcab089e 76 * grayscale data update. However, I've seen some slight
mjr 33:d832bcab089e 77 * instability in the signal in my breadboard setup using the
mjr 33:d832bcab089e 78 * full 30MHz, so I've reduced this slightly, which seems to
mjr 33:d832bcab089e 79 * yield a solid signal. The limit will vary according to how
mjr 33:d832bcab089e 80 * clean the signal path is to the chips; you can probably crank
mjr 33:d832bcab089e 81 * this up to full speed if you have a well-designed PCB, good
mjr 33:d832bcab089e 82 * decoupling capacitors near the 5940 VCC/GND pins, and short
mjr 33:d832bcab089e 83 * wires between the KL25Z and the PCB. A short, clean path to
mjr 33:d832bcab089e 84 * KL25Z ground seems especially important.
mjr 26:cb71c4af2912 85 *
mjr 26:cb71c4af2912 86 * The SPI clock must be fast enough that the data transmission
mjr 26:cb71c4af2912 87 * time for a full update is comfortably less than the blanking
mjr 26:cb71c4af2912 88 * cycle time. The grayscale refresh requires 192 bits per TLC5940
mjr 26:cb71c4af2912 89 * in the daisy chain, and each bit takes one SPI clock to send.
mjr 26:cb71c4af2912 90 * Our reference setup in the Pinscape controller allows for up to
mjr 26:cb71c4af2912 91 * 4 TLC5940s, so a full refresh cycle on a fully populated system
mjr 26:cb71c4af2912 92 * would be 768 SPI clocks. The blanking cycle is 4096 GSCLK cycles.
mjr 26:cb71c4af2912 93 *
mjr 26:cb71c4af2912 94 * t(blank) = 4096 * 1/GSCLK_SPEED
mjr 26:cb71c4af2912 95 * t(refresh) = 768 * 1/SPI_SPEED
mjr 26:cb71c4af2912 96 * Therefore: SPI_SPEED must be > 768/4096 * GSCLK_SPEED
mjr 26:cb71c4af2912 97 *
mjr 26:cb71c4af2912 98 * Since the SPI speed can be so high, and since we want to keep
mjr 26:cb71c4af2912 99 * the GSCLK speed relatively low, the constraint above simply
mjr 26:cb71c4af2912 100 * isn't a factor. E.g., at SPI=30MHz and GSCLK=500kHz,
mjr 26:cb71c4af2912 101 * t(blank) is 8192us and t(refresh) is 25us.
mjr 26:cb71c4af2912 102 */
mjr 38:091e511ce8a0 103 #define SPI_SPEED 28000000
mjr 26:cb71c4af2912 104
mjr 26:cb71c4af2912 105 /**
mjr 26:cb71c4af2912 106 * The rate at which the GSCLK pin is pulsed. This also controls
mjr 26:cb71c4af2912 107 * how often the reset function is called. The reset function call
mjr 38:091e511ce8a0 108 * interval is (1/GSCLK_SPEED) * 4096. The maximum reliable rate is
mjr 26:cb71c4af2912 109 * around 32Mhz. It's best to keep this rate as low as possible:
mjr 26:cb71c4af2912 110 * the higher the rate, the higher the refresh() call frequency,
mjr 40:cc0d9814522b 111 * so the higher the CPU load. Higher frequencies also make it more
mjr 40:cc0d9814522b 112 * challenging to wire the chips for clean signal transmission, so
mjr 40:cc0d9814522b 113 * minimizing the clock speed will help with signal stability.
mjr 26:cb71c4af2912 114 *
mjr 40:cc0d9814522b 115 * The lower bound depends on the application. For driving lights,
mjr 40:cc0d9814522b 116 * the limiting factor is flicker: the lower the rate, the more
mjr 40:cc0d9814522b 117 * noticeable the flicker. Incandescents tend to look flicker-free
mjr 40:cc0d9814522b 118 * at about 50 Hz (205 kHz grayscale clock). LEDs need slightly
mjr 40:cc0d9814522b 119 * faster rates.
mjr 26:cb71c4af2912 120 */
mjr 40:cc0d9814522b 121 #define GSCLK_SPEED 350000
mjr 26:cb71c4af2912 122
mjr 26:cb71c4af2912 123 /**
mjr 26:cb71c4af2912 124 * This class controls a TLC5940 PWM driver IC.
mjr 26:cb71c4af2912 125 *
mjr 26:cb71c4af2912 126 * Using the TLC5940 class to control an LED:
mjr 26:cb71c4af2912 127 * @code
mjr 26:cb71c4af2912 128 * #include "mbed.h"
mjr 26:cb71c4af2912 129 * #include "TLC5940.h"
mjr 26:cb71c4af2912 130 *
mjr 26:cb71c4af2912 131 * // Create the TLC5940 instance
mjr 26:cb71c4af2912 132 * TLC5940 tlc(p7, p5, p21, p9, p10, p11, p12, 1);
mjr 26:cb71c4af2912 133 *
mjr 26:cb71c4af2912 134 * int main()
mjr 26:cb71c4af2912 135 * {
mjr 26:cb71c4af2912 136 * // Enable the first LED
mjr 26:cb71c4af2912 137 * tlc.set(0, 0xfff);
mjr 26:cb71c4af2912 138 *
mjr 26:cb71c4af2912 139 * while(1)
mjr 26:cb71c4af2912 140 * {
mjr 26:cb71c4af2912 141 * }
mjr 26:cb71c4af2912 142 * }
mjr 26:cb71c4af2912 143 * @endcode
mjr 26:cb71c4af2912 144 */
mjr 26:cb71c4af2912 145 class TLC5940
mjr 26:cb71c4af2912 146 {
mjr 26:cb71c4af2912 147 public:
mjr 26:cb71c4af2912 148 /**
mjr 26:cb71c4af2912 149 * Set up the TLC5940
mjr 26:cb71c4af2912 150 * @param SCLK - The SCK pin of the SPI bus
mjr 26:cb71c4af2912 151 * @param MOSI - The MOSI pin of the SPI bus
mjr 26:cb71c4af2912 152 * @param GSCLK - The GSCLK pin of the TLC5940(s)
mjr 26:cb71c4af2912 153 * @param BLANK - The BLANK pin of the TLC5940(s)
mjr 26:cb71c4af2912 154 * @param XLAT - The XLAT pin of the TLC5940(s)
mjr 26:cb71c4af2912 155 * @param nchips - The number of TLC5940s (if you are daisy chaining)
mjr 26:cb71c4af2912 156 */
mjr 26:cb71c4af2912 157 TLC5940(PinName SCLK, PinName MOSI, PinName GSCLK, PinName BLANK, PinName XLAT, int nchips)
mjr 47:df7a88cd249c 158 : sdma(DMAch_TLC5940),
mjr 47:df7a88cd249c 159 spi(MOSI, NC, SCLK),
mjr 26:cb71c4af2912 160 gsclk(GSCLK),
mjr 26:cb71c4af2912 161 blank(BLANK),
mjr 26:cb71c4af2912 162 xlat(XLAT),
mjr 33:d832bcab089e 163 nchips(nchips)
mjr 26:cb71c4af2912 164 {
mjr 40:cc0d9814522b 165 // start up initially disabled
mjr 40:cc0d9814522b 166 enabled = false;
mjr 40:cc0d9814522b 167
mjr 33:d832bcab089e 168 // set XLAT to initially off
mjr 30:6e9902f06f48 169 xlat = 0;
mjr 33:d832bcab089e 170
mjr 33:d832bcab089e 171 // Assert BLANK while starting up, to keep the outputs turned off until
mjr 33:d832bcab089e 172 // everything is stable. This helps prevent spurious flashes during startup.
mjr 33:d832bcab089e 173 // (That's not particularly important for lights, but it matters more for
mjr 33:d832bcab089e 174 // tactile devices. It's a bit alarming to fire a replay knocker on every
mjr 33:d832bcab089e 175 // power-on, for example.)
mjr 30:6e9902f06f48 176 blank = 1;
mjr 30:6e9902f06f48 177
mjr 26:cb71c4af2912 178 // Configure SPI format and speed. Note that KL25Z ONLY supports 8-bit
mjr 26:cb71c4af2912 179 // mode. The TLC5940 nominally requires 12-bit data blocks for the
mjr 26:cb71c4af2912 180 // grayscale levels, but SPI is ultimately just a bit-level serial format,
mjr 26:cb71c4af2912 181 // so we can reformat the 12-bit blocks into 8-bit bytes to fit the
mjr 26:cb71c4af2912 182 // KL25Z's limits. This should work equally well on other microcontrollers
mjr 38:091e511ce8a0 183 // that are more flexible. The TLC5940 requires polarity/phase format 0.
mjr 26:cb71c4af2912 184 spi.format(8, 0);
mjr 26:cb71c4af2912 185 spi.frequency(SPI_SPEED);
mjr 33:d832bcab089e 186
mjr 33:d832bcab089e 187 // Send out a full data set to the chips, to clear out any random
mjr 33:d832bcab089e 188 // startup data from the registers. Include some extra bits - there
mjr 33:d832bcab089e 189 // are some cases (such as after sending dot correct commands) where
mjr 33:d832bcab089e 190 // an extra bit per chip is required, and the initial state is
mjr 33:d832bcab089e 191 // somewhat unpredictable, so send extra just to make sure we cover
mjr 33:d832bcab089e 192 // all bases. This does no harm; extra bits just fall off the end of
mjr 33:d832bcab089e 193 // the daisy chain, and since we want all registers set to 0, we can
mjr 33:d832bcab089e 194 // send arbitrarily many extra 0's.
mjr 33:d832bcab089e 195 for (int i = 0 ; i < nchips*25 ; ++i)
mjr 33:d832bcab089e 196 spi.write(0);
mjr 33:d832bcab089e 197
mjr 33:d832bcab089e 198 // do an initial XLAT to latch all of these "0" values into the
mjr 33:d832bcab089e 199 // grayscale registers
mjr 33:d832bcab089e 200 xlat = 1;
mjr 33:d832bcab089e 201 xlat = 0;
mjr 29:582472d0bc57 202
mjr 39:b3815a1c3802 203 // Allocate our DMA buffers. The transfer on each cycle is 192 bits per
mjr 40:cc0d9814522b 204 // chip = 24 bytes per chip. Allocate two buffers, so that we have a
mjr 40:cc0d9814522b 205 // stable buffer that we can send to the chips, and a separate working
mjr 40:cc0d9814522b 206 // copy that we can asynchronously update.
mjr 40:cc0d9814522b 207 dmalen = nchips*24;
mjr 40:cc0d9814522b 208 dmabuf = new uint8_t[dmalen*2];
mjr 40:cc0d9814522b 209 memset(dmabuf, 0, dmalen*2);
mjr 26:cb71c4af2912 210
mjr 40:cc0d9814522b 211 zerobuf = new uint8_t[dmalen];//$$$
mjr 40:cc0d9814522b 212 memset(zerobuf, 0xff, dmalen);//$$$
mjr 40:cc0d9814522b 213
mjr 40:cc0d9814522b 214 // start with buffer 0 live, with no new data pending
mjr 40:cc0d9814522b 215 livebuf = dmabuf;
mjr 40:cc0d9814522b 216 workbuf = dmabuf + dmalen;
mjr 40:cc0d9814522b 217 dirty = false;
mjr 40:cc0d9814522b 218
mjr 30:6e9902f06f48 219 // Set up the Simple DMA interface object. We use the DMA controller to
mjr 30:6e9902f06f48 220 // send grayscale data updates to the TLC5940 chips. This lets the CPU
mjr 30:6e9902f06f48 221 // keep running other tasks while we send gs updates, and importantly
mjr 30:6e9902f06f48 222 // allows our blanking interrupt handler return almost immediately.
mjr 30:6e9902f06f48 223 // The DMA transfer is from our internal DMA buffer to SPI0, which is
mjr 30:6e9902f06f48 224 // the SPI controller physically connected to the TLC5940s.
mjr 40:cc0d9814522b 225 sdma.source(livebuf, true, 8);
mjr 38:091e511ce8a0 226 sdma.destination(&(SPI0->D), false, 8);
mjr 30:6e9902f06f48 227 sdma.trigger(Trigger_SPI0_TX);
mjr 30:6e9902f06f48 228 sdma.attach(this, &TLC5940::dmaDone);
mjr 30:6e9902f06f48 229
mjr 30:6e9902f06f48 230 // Enable DMA on SPI0. SimpleDMA doesn't do this for us; we have to
mjr 30:6e9902f06f48 231 // do it explicitly. This is just a matter of setting bit 5 (TXDMAE)
mjr 38:091e511ce8a0 232 // in the SPI controller's Control Register 2 (C2).
mjr 30:6e9902f06f48 233 SPI0->C2 |= 0x20; // set bit 5 = 0x20 = TXDMAE in SPI0 control register 2
mjr 30:6e9902f06f48 234
mjr 30:6e9902f06f48 235 // Configure the GSCLK output's frequency
mjr 26:cb71c4af2912 236 gsclk.period(1.0/GSCLK_SPEED);
mjr 33:d832bcab089e 237
mjr 33:d832bcab089e 238 // mark that we need an initial update
mjr 40:cc0d9814522b 239 dirty = true;
mjr 33:d832bcab089e 240 needXlat = false;
mjr 40:cc0d9814522b 241 }
mjr 40:cc0d9814522b 242
mjr 40:cc0d9814522b 243 // Global enable/disble. When disabled, we assert the blanking signal
mjr 40:cc0d9814522b 244 // continuously to keep all outputs turned off. This can be used during
mjr 40:cc0d9814522b 245 // startup and sleep mode to prevent spurious output signals from
mjr 40:cc0d9814522b 246 // uninitialized grayscale registers. The chips have random values in
mjr 40:cc0d9814522b 247 // their internal registers when power is first applied, so we have to
mjr 40:cc0d9814522b 248 // explicitly send the initial zero levels after power cycling the chips.
mjr 40:cc0d9814522b 249 // The chips might not have power even when the KL25Z is running, because
mjr 40:cc0d9814522b 250 // they might be powered from a separate power supply from the KL25Z
mjr 40:cc0d9814522b 251 // (the Pinscape Expansion Boards work this way). Global blanking helps
mjr 40:cc0d9814522b 252 // us start up more cleanly by suppressing all outputs until we can be
mjr 40:cc0d9814522b 253 // reasonably sure that the various chip registers are initialized.
mjr 40:cc0d9814522b 254 void enable(bool f)
mjr 40:cc0d9814522b 255 {
mjr 40:cc0d9814522b 256 // note the new setting
mjr 40:cc0d9814522b 257 enabled = f;
mjr 40:cc0d9814522b 258
mjr 40:cc0d9814522b 259 // if disabled, apply blanking immediately
mjr 40:cc0d9814522b 260 if (!f)
mjr 40:cc0d9814522b 261 {
mjr 40:cc0d9814522b 262 gsclk.write(0);
mjr 40:cc0d9814522b 263 blank = 1;
mjr 40:cc0d9814522b 264 }
mjr 40:cc0d9814522b 265
mjr 40:cc0d9814522b 266 // do a full update with the new setting
mjr 40:cc0d9814522b 267 dirty = true;
mjr 40:cc0d9814522b 268 }
mjr 29:582472d0bc57 269
mjr 30:6e9902f06f48 270 // Start the clock running
mjr 29:582472d0bc57 271 void start()
mjr 29:582472d0bc57 272 {
mjr 26:cb71c4af2912 273 // Set up the first call to the reset function, which asserts BLANK to
mjr 26:cb71c4af2912 274 // end the PWM cycle and handles new grayscale data output and latching.
mjr 26:cb71c4af2912 275 // The original version of this library uses a timer to call reset
mjr 26:cb71c4af2912 276 // periodically, but that approach is somewhat problematic because the
mjr 26:cb71c4af2912 277 // reset function itself takes a small amount of time to run, so the
mjr 26:cb71c4af2912 278 // *actual* cycle is slightly longer than what we get from counting
mjr 26:cb71c4af2912 279 // GS clocks. Running reset on a timer therefore causes the calls to
mjr 26:cb71c4af2912 280 // slip out of phase with the actual full cycles, which causes
mjr 26:cb71c4af2912 281 // premature blanking that shows up as visible flicker. To get the
mjr 26:cb71c4af2912 282 // reset cycle to line up exactly with a full PWM cycle, it works
mjr 26:cb71c4af2912 283 // better to set up a new timer on each cycle, *after* we've finished
mjr 26:cb71c4af2912 284 // with the somewhat unpredictable overhead of the interrupt handler.
mjr 26:cb71c4af2912 285 // This ensures that we'll get much closer to exact alignment of the
mjr 26:cb71c4af2912 286 // cycle phase, and in any case the worst that happens is that some
mjr 26:cb71c4af2912 287 // cycles are very slightly too long or short (due to imperfections
mjr 26:cb71c4af2912 288 // in the timer clock vs the PWM clock that determines the GSCLCK
mjr 26:cb71c4af2912 289 // output to the TLC5940), which is far less noticeable than a
mjr 26:cb71c4af2912 290 // constantly rotating phase misalignment.
mjr 38:091e511ce8a0 291 resetTimer.attach(this, &TLC5940::reset, (1.0/GSCLK_SPEED)*4096.0);
mjr 26:cb71c4af2912 292 }
mjr 26:cb71c4af2912 293
mjr 26:cb71c4af2912 294 ~TLC5940()
mjr 26:cb71c4af2912 295 {
mjr 30:6e9902f06f48 296 delete [] dmabuf;
mjr 26:cb71c4af2912 297 }
mjr 26:cb71c4af2912 298
mjr 39:b3815a1c3802 299 /*
mjr 39:b3815a1c3802 300 * Set an output
mjr 26:cb71c4af2912 301 */
mjr 26:cb71c4af2912 302 void set(int idx, unsigned short data)
mjr 26:cb71c4af2912 303 {
mjr 39:b3815a1c3802 304 // validate the index
mjr 39:b3815a1c3802 305 if (idx >= 0 && idx < nchips*16)
mjr 39:b3815a1c3802 306 {
mjr 40:cc0d9814522b 307 // this is a critical section, since we're updating a static buffer and
mjr 40:cc0d9814522b 308 // can call this routine from application context or interrupt context
mjr 40:cc0d9814522b 309 __disable_irq();
mjr 40:cc0d9814522b 310
mjr 40:cc0d9814522b 311 // If the buffer isn't dirty, it means that the previous working buffer
mjr 40:cc0d9814522b 312 // was swapped into the live buffer on the last blanking interval. This
mjr 40:cc0d9814522b 313 // means that the working buffer hasn't been updated to the live data yet,
mjr 40:cc0d9814522b 314 // so we need to copy it now.
mjr 40:cc0d9814522b 315 if (!dirty)
mjr 40:cc0d9814522b 316 {
mjr 40:cc0d9814522b 317 memcpy(workbuf, livebuf, dmalen);
mjr 40:cc0d9814522b 318 dirty = true;
mjr 40:cc0d9814522b 319 }
mjr 40:cc0d9814522b 320
mjr 39:b3815a1c3802 321 // Figure the DMA buffer location of the data. The DMA buffer has the
mjr 39:b3815a1c3802 322 // packed bit format that we send across the wire, with 12 bits per output,
mjr 39:b3815a1c3802 323 // arranged from last output to first output (N = number of outputs = nchips*16):
mjr 39:b3815a1c3802 324 //
mjr 39:b3815a1c3802 325 // byte 0 = high 8 bits of output N-1
mjr 39:b3815a1c3802 326 // 1 = low 4 bits of output N-1 | high 4 bits of output N-2
mjr 39:b3815a1c3802 327 // 2 = low 8 bits of N-2
mjr 39:b3815a1c3802 328 // 3 = high 8 bits of N-3
mjr 39:b3815a1c3802 329 // 4 = low 4 bits of N-3 | high 4 bits of N-2
mjr 39:b3815a1c3802 330 // 5 = low 8bits of N-4
mjr 39:b3815a1c3802 331 // ...
mjr 39:b3815a1c3802 332 // 24*nchips-3 = high 8 bits of output 1
mjr 39:b3815a1c3802 333 // 24*nchips-2 = low 4 bits of output 1 | high 4 bits of output 0
mjr 39:b3815a1c3802 334 // 24*nchips-1 = low 8 bits of output 0
mjr 39:b3815a1c3802 335 //
mjr 39:b3815a1c3802 336 // So this update will affect two bytes. If the output number if even, we're
mjr 39:b3815a1c3802 337 // in the high 4 + low 8 pair; if odd, we're in the high 8 + low 4 pair.
mjr 39:b3815a1c3802 338 int di = nchips*24 - 3 - (3*(idx/2));
mjr 39:b3815a1c3802 339 if (idx & 1)
mjr 39:b3815a1c3802 340 {
mjr 39:b3815a1c3802 341 // ODD = high 8 | low 4
mjr 40:cc0d9814522b 342 workbuf[di] = uint8_t((data >> 4) & 0xff);
mjr 40:cc0d9814522b 343 workbuf[di+1] &= 0x0F;
mjr 40:cc0d9814522b 344 workbuf[di+1] |= uint8_t((data << 4) & 0xf0);
mjr 39:b3815a1c3802 345 }
mjr 39:b3815a1c3802 346 else
mjr 39:b3815a1c3802 347 {
mjr 39:b3815a1c3802 348 // EVEN = high 4 | low 8
mjr 40:cc0d9814522b 349 workbuf[di+1] &= 0xF0;
mjr 40:cc0d9814522b 350 workbuf[di+1] |= uint8_t((data >> 8) & 0x0f);
mjr 40:cc0d9814522b 351 workbuf[di+2] = uint8_t(data & 0xff);
mjr 39:b3815a1c3802 352 }
mjr 39:b3815a1c3802 353
mjr 40:cc0d9814522b 354 // end the critical section
mjr 40:cc0d9814522b 355 __enable_irq();
mjr 39:b3815a1c3802 356 }
mjr 26:cb71c4af2912 357 }
mjr 40:cc0d9814522b 358
mjr 40:cc0d9814522b 359 // Update the outputs. We automatically update the outputs on the grayscale timer
mjr 40:cc0d9814522b 360 // when we have pending changes, so it's not necessary to call this explicitly after
mjr 40:cc0d9814522b 361 // making a change via set(). This can be called to force an update when the chips
mjr 40:cc0d9814522b 362 // might be out of sync with our internal state, such as after power-on.
mjr 40:cc0d9814522b 363 void update(bool force = false)
mjr 40:cc0d9814522b 364 {
mjr 40:cc0d9814522b 365 if (force)
mjr 40:cc0d9814522b 366 dirty = true;
mjr 40:cc0d9814522b 367 }
mjr 26:cb71c4af2912 368
mjr 26:cb71c4af2912 369 private:
mjr 26:cb71c4af2912 370 // current level for each output
mjr 26:cb71c4af2912 371 unsigned short *gs;
mjr 26:cb71c4af2912 372
mjr 30:6e9902f06f48 373 // Simple DMA interface object
mjr 30:6e9902f06f48 374 SimpleDMA sdma;
mjr 30:6e9902f06f48 375
mjr 40:cc0d9814522b 376 // DMA transfer buffers - double buffer. Each time we have data to transmit to the
mjr 40:cc0d9814522b 377 // TLC5940 chips, we format the data into the working half of this buffer exactly as
mjr 40:cc0d9814522b 378 // it will go across the wire, then hand the buffer to the DMA controller to move
mjr 40:cc0d9814522b 379 // through the SPI port. This memory block is actually two buffers, one live and
mjr 40:cc0d9814522b 380 // one pending. When we're ready to send updates to the chips, we swap the working
mjr 40:cc0d9814522b 381 // buffer into the live buffer so that we can send the latest updates. We keep a
mjr 40:cc0d9814522b 382 // separate working copy so that our live copy is stable, so that we don't alter
mjr 40:cc0d9814522b 383 // any data in the midst of an asynchronous DMA transmission to the chips.
mjr 40:cc0d9814522b 384 uint8_t *dmabuf;
mjr 40:cc0d9814522b 385
mjr 40:cc0d9814522b 386 uint8_t *zerobuf; // $$$ buffer for all zeroes to flush chip registers when no updates are needed
mjr 40:cc0d9814522b 387
mjr 40:cc0d9814522b 388 // The working and live buffer pointers. At any give time, one buffer is live and
mjr 40:cc0d9814522b 389 // the other is active.
mjr 40:cc0d9814522b 390 // dmabuf1 is live and the other is the working buffer. When there's pending work,
mjr 40:cc0d9814522b 391 // we swap them to make the pending data live.
mjr 40:cc0d9814522b 392 uint8_t *livebuf;
mjr 40:cc0d9814522b 393 uint8_t *workbuf;
mjr 40:cc0d9814522b 394
mjr 40:cc0d9814522b 395 // length of each DMA buffer, in bytes - 12 bits = 1.5 bytes per output, 16 outputs
mjr 40:cc0d9814522b 396 // per chip -> 24 bytes per chip
mjr 40:cc0d9814522b 397 uint16_t dmalen;
mjr 40:cc0d9814522b 398
mjr 40:cc0d9814522b 399 // Dirty: true means that the non-live buffer has new pending data. False means
mjr 40:cc0d9814522b 400 // that the non-live buffer is empty.
mjr 40:cc0d9814522b 401 bool dirty;
mjr 40:cc0d9814522b 402
mjr 40:cc0d9814522b 403 // Enabled: this enables or disables all outputs. When this is true, we assert the
mjr 40:cc0d9814522b 404 // BLANK signal continuously.
mjr 40:cc0d9814522b 405 bool enabled;
mjr 30:6e9902f06f48 406
mjr 26:cb71c4af2912 407 // SPI port - only MOSI and SCK are used
mjr 26:cb71c4af2912 408 SPI spi;
mjr 26:cb71c4af2912 409
mjr 26:cb71c4af2912 410 // use a PWM out for the grayscale clock - this provides a stable
mjr 26:cb71c4af2912 411 // square wave signal without consuming CPU
mjr 26:cb71c4af2912 412 FastPWM gsclk;
mjr 26:cb71c4af2912 413
mjr 26:cb71c4af2912 414 // Digital out pins used for the TLC5940
mjr 26:cb71c4af2912 415 DigitalOut blank;
mjr 26:cb71c4af2912 416 DigitalOut xlat;
mjr 26:cb71c4af2912 417
mjr 26:cb71c4af2912 418 // number of daisy-chained TLC5940s we're controlling
mjr 26:cb71c4af2912 419 int nchips;
mjr 26:cb71c4af2912 420
mjr 26:cb71c4af2912 421 // Timeout to end each PWM cycle. This is a one-shot timer that we reset
mjr 26:cb71c4af2912 422 // on each cycle.
mjr 38:091e511ce8a0 423 Timeout resetTimer;
mjr 26:cb71c4af2912 424
mjr 33:d832bcab089e 425 // Do we need an XLAT signal on the next blanking interval?
mjr 33:d832bcab089e 426 volatile bool needXlat;
mjr 40:cc0d9814522b 427 volatile bool newGSData;//$$$
mjr 26:cb71c4af2912 428
mjr 40:cc0d9814522b 429 // Reset the grayscale cycle and send the next data update
mjr 26:cb71c4af2912 430 void reset()
mjr 26:cb71c4af2912 431 {
mjr 30:6e9902f06f48 432 // start the blanking cycle
mjr 30:6e9902f06f48 433 startBlank();
mjr 33:d832bcab089e 434
mjr 40:cc0d9814522b 435 // if we have pending grayscale data, update the DMA data
mjr 40:cc0d9814522b 436 /*$$$bool*/ newGSData = false;
mjr 40:cc0d9814522b 437 if (dirty)
mjr 40:cc0d9814522b 438 {
mjr 40:cc0d9814522b 439 // swap live and working buffers
mjr 40:cc0d9814522b 440 uint8_t *tmp = livebuf;
mjr 40:cc0d9814522b 441 livebuf = workbuf;
mjr 40:cc0d9814522b 442 workbuf = tmp;
mjr 40:cc0d9814522b 443
mjr 40:cc0d9814522b 444 // set the new DMA source
mjr 40:cc0d9814522b 445 sdma.source(livebuf, true, 8);
mjr 40:cc0d9814522b 446
mjr 40:cc0d9814522b 447 // no longer dirty
mjr 40:cc0d9814522b 448 dirty = false;
mjr 40:cc0d9814522b 449
mjr 40:cc0d9814522b 450 // note the new data
mjr 40:cc0d9814522b 451 newGSData = true;
mjr 40:cc0d9814522b 452 }
mjr 40:cc0d9814522b 453 else { sdma.source(zerobuf, true, 8); }//$$$
mjr 40:cc0d9814522b 454
mjr 33:d832bcab089e 455 #if DATA_UPDATE_INSIDE_BLANKING
mjr 33:d832bcab089e 456 // We're configured to send the new GS data entirely within
mjr 33:d832bcab089e 457 // the blanking interval. Start the DMA transfer now, and
mjr 33:d832bcab089e 458 // return without ending the blanking interval. The DMA
mjr 33:d832bcab089e 459 // completion interrupt handler will do that when the data
mjr 33:d832bcab089e 460 // update has completed.
mjr 33:d832bcab089e 461 //
mjr 33:d832bcab089e 462 // Note that we do the data update/ unconditionally in the
mjr 33:d832bcab089e 463 // send-during-blanking case, whether or not we have new GS
mjr 33:d832bcab089e 464 // data. This is because the update causes a 0.3% reduction
mjr 33:d832bcab089e 465 // in brightness because of the elongated BLANK interval.
mjr 33:d832bcab089e 466 // That would be visible as a flicker on each update if we
mjr 33:d832bcab089e 467 // did updates on some cycles and not others. By doing an
mjr 33:d832bcab089e 468 // update on every cycle, we make the brightness reduction
mjr 33:d832bcab089e 469 // uniform across time, which makes it less perceptible.
mjr 40:cc0d9814522b 470 sdma.start(dmalen);
mjr 33:d832bcab089e 471
mjr 33:d832bcab089e 472 #else // DATA_UPDATE_INSIDE_BLANKING
mjr 33:d832bcab089e 473
mjr 33:d832bcab089e 474 // end the blanking interval
mjr 33:d832bcab089e 475 endBlank();
mjr 33:d832bcab089e 476
mjr 40:cc0d9814522b 477 // send out the DMA contents if we have new data
mjr 40:cc0d9814522b 478 //$$$ if (newGSData)
mjr 40:cc0d9814522b 479 sdma.start(dmalen);
mjr 26:cb71c4af2912 480
mjr 33:d832bcab089e 481 #endif // DATA_UPDATE_INSIDE_BLANKING
mjr 30:6e9902f06f48 482 }
mjr 30:6e9902f06f48 483
mjr 30:6e9902f06f48 484 void startBlank()
mjr 30:6e9902f06f48 485 {
mjr 30:6e9902f06f48 486 // turn off the grayscale clock, and assert BLANK to end the grayscale cycle
mjr 30:6e9902f06f48 487 gsclk.write(0);
mjr 40:cc0d9814522b 488 blank = 0; // for a slight delay - chip requires 20ns GSCLK up to BLANK up
mjr 30:6e9902f06f48 489 blank = 1;
mjr 30:6e9902f06f48 490 }
mjr 26:cb71c4af2912 491
mjr 33:d832bcab089e 492 void endBlank()
mjr 30:6e9902f06f48 493 {
mjr 33:d832bcab089e 494 // if we've sent new grayscale data since the last blanking
mjr 33:d832bcab089e 495 // interval, latch it by asserting XLAT
mjr 33:d832bcab089e 496 if (needXlat)
mjr 30:6e9902f06f48 497 {
mjr 26:cb71c4af2912 498 // latch the new data while we're still blanked
mjr 26:cb71c4af2912 499 xlat = 1;
mjr 26:cb71c4af2912 500 xlat = 0;
mjr 33:d832bcab089e 501 needXlat = false;
mjr 26:cb71c4af2912 502 }
mjr 26:cb71c4af2912 503
mjr 40:cc0d9814522b 504 // End the blanking interval and restart the grayscale clock. Note
mjr 40:cc0d9814522b 505 // that we keep the blanking on if the chips are globally disabled.
mjr 40:cc0d9814522b 506 blank = enabled ? 0 : 1;
mjr 26:cb71c4af2912 507 gsclk.write(.5);
mjr 26:cb71c4af2912 508
mjr 26:cb71c4af2912 509 // set up the next blanking interrupt
mjr 38:091e511ce8a0 510 resetTimer.attach(this, &TLC5940::reset, (1.0/GSCLK_SPEED)*4096.0);
mjr 26:cb71c4af2912 511 }
mjr 26:cb71c4af2912 512
mjr 30:6e9902f06f48 513 // Interrupt handler for DMA completion. The DMA controller calls this
mjr 30:6e9902f06f48 514 // when it finishes with the transfer request we set up above. When the
mjr 30:6e9902f06f48 515 // transfer is done, we simply end the blanking cycle and start a new
mjr 30:6e9902f06f48 516 // grayscale cycle.
mjr 30:6e9902f06f48 517 void dmaDone()
mjr 30:6e9902f06f48 518 {
mjr 33:d832bcab089e 519 // mark that we need to assert XLAT to latch the new
mjr 33:d832bcab089e 520 // grayscale data during the next blanking interval
mjr 40:cc0d9814522b 521 needXlat = newGSData;//$$$ true;
mjr 33:d832bcab089e 522
mjr 33:d832bcab089e 523 #if DATA_UPDATE_INSIDE_BLANKING
mjr 33:d832bcab089e 524 // we're doing the gs update within the blanking cycle, so end
mjr 33:d832bcab089e 525 // the blanking cycle now that the transfer has completed
mjr 33:d832bcab089e 526 endBlank();
mjr 33:d832bcab089e 527 #endif
mjr 30:6e9902f06f48 528 }
mjr 30:6e9902f06f48 529
mjr 26:cb71c4af2912 530 };
mjr 26:cb71c4af2912 531
mjr 26:cb71c4af2912 532 #endif