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 mechanical plunger, button inputs, and feedback device control.

In case you haven't heard of the idea 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 show the backglass artwork. Some cabs also include a third monitor to simulate the DMD (Dot Matrix Display) used for scoring on 1990s machines, or even an original plasma DMD. A computer (usually a Windows PC) 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 trim hardware.

It's possible to buy a pre-built virtual pinball machine, but it also makes a great 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 potentiometer (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 KL25Z can only run one firmware program at a time, so if you install the Pinscape firmware on your KL25Z, it will replace and erase your existing VirtuaPin proprietary firmware. If you do this, the only way to restore your VirtuaPin firmware is to physically ship the KL25Z back to VirtuaPin and ask them to re-flash it. They don't allow you to do this at home, and they don't even allow you to back up your firmware, since they want to protect their proprietary software from copying. For all of these reasons, if you want to run the Pinscape software, I strongly recommend that you buy a "blank" retail KL25Z to use with Pinscape. They only cost about $15 and are available at several online retailers, including Amazon, Mouser, and eBay. The blank retail boards don't come with any proprietary firmware pre-installed, so installing Pinscape won't delete anything that you paid extra for.

With those warnings in mind, if you're absolutely sure that you don't mind permanently erasing your VirtuaPin firmware, it is at least possible to use Pinscape as a replacement for the VirtuaPin firmware. Pinscape uses the same button wiring conventions as the VirtuaPin setup, so you can keep your buttons (although you'll have to update the GPIO pin mappings in the Config Tool to match your physical wiring). As of the June, 2021 firmware, the Vishay VCNL4010 plunger sensor that comes with the VirtuaPin v3 plunger kit is supported, so you can also keep your plunger, if you have that chip. (You should check to be sure that's the sensor chip you have before committing to this route, if keeping the plunger sensor is important to you. The older VirtuaPin plunger kits came with different IR sensors that the Pinscape software doesn't handle.)

Revision:
79:682ae3171a08
Parent:
77:0b96f6867312
Child:
80:94dc2946871b
--- a/FreescaleIAP/FreescaleIAP.cpp	Sun Mar 19 05:30:53 2017 +0000
+++ b/FreescaleIAP/FreescaleIAP.cpp	Thu Mar 23 05:19:05 2017 +0000
@@ -1,67 +1,55 @@
-// FreescaleIAP, private version
+// FreescaleIAP - custom version
 //
-// This is a heavily modified version of Erik Olieman's FreescaleIAP, a
-// flash memory writer for Freescale boards.  This version is adapted to
-// the special needs of the KL25Z.
-//
-// Simplifications:
+// This is a simplified version of Erik Olieman's FreescaleIAP, a flash 
+// memory writer for Freescale boards.  This version combines erase, write,
+// and verify into a single API call.  The caller only has to give us a
+// buffer (of any length) to write, and the address to write it to, and
+// we'll do the whole thing - essentially a memcpy() to flash.
 //
-// Unlike EO's original version, this version combines erase and write
-// into a single opreation, so the caller can simply give us a buffer
-// and a location, and we'll write it, including the erase prep.  We
-// don't need to be able to separate the operations, so the combined
-// interface is simpler at the API level and also lets us do all of the
-// interrupt masking in one place (see below).
-//
-// Stability improvements:
+// This version uses an assembler implementation of the core code that
+// launches an FTFA command and waits for completion, to minimize the
+// size of the code and to ensure that it's placed in RAM.  The KL25Z
+// flash controller prohibits any flash reads while an FTFA command is
+// executing.  This includes instruction fetches; any instruction fetch
+// from flash while an FTFA command is running will fail, which will 
+// freeze the CPU.  Placing the execute/wait code in RAM ensures that
+// the wait loop itself won't trigger a fetch.  It's also vital to disable
+// interrupts while the execute/wait code is running, to ensure that we
+// don't jump to an ISR in flash during the wait.
 //
-// The KL25Z has an important restriction on flash writing that makes it
-// very delicate.  Specifically, the flash controller (FTFA) doesn't allow 
-// any read operations while a sector erase is in progress.  This complicates
-// things for a KL25Z app because all program code is stored in flash by 
-// default.  This means that every instruction fetch is a flash read.  The
-// FTFA's response to a read while an erase is in progress is to fail the
-// read.  When the read is actually an instruction fetch, this results in
-// CPU lockup.  Making this even more complicated, the erase operation can
-// only operate on a whole sector at a time, which takes on the order of 
-// milliseconds, which is a very long time for the CPU to go without any
-// instruction fetches.  Even if the code that initiates the erase is 
-// located in RAM and is very careful to loop within the RAM code block,
-// any interrupt could take us out of the RAM loop and trigger a fetch
-// on a flash location.
-//
-// We use two strategies to avoid flash fetches while we're working.
-// First, the code that performs all of the FTFA operations is written
-// in assembly, in a module AREA marked READWRITE.  This forces the
-// linker to put the code in RAM.  The code could otherwise just have
-// well been written in C++, but as far as I know there's no way to tell
-// the mbed C++ compiler to put code in RAM.  Since the FTFA code is all
-// in RAM, it doesn't by itself trigger any flash fetches as it executes,
-// so we're left with interrupts as the only concern.  Second, we explicitly 
-// disable all of the peripheral interrupts that we use anywhere in the 
-// program (USB, all the timers, GPIO ports, etc) via the NVIC.  From
-// testing, it's clear that disabling interrupts at the CPU level via
-// __disable_irq() (or the equivalent assembly instruction CPSID I) isn't
-// enough.  We have to turn interrupts off at the peripheral (NVIC) level.
-// I'm really not sure why this is required, since you'd think the CPSID I
-// masking would be enough, but experimentally it's clearly not.  This is
-// a detail of ARM hardware architecture that I need to look into more,
-// since it leaves me uneasy that there might be even more subtleties 
-// left to uncover.   But at least things seem very stable after blocking
-// interrupts at the NVIC level.
+// Despite the dire warnings in the hardware reference manual about putting
+// the FTFA execute/wait code in RAM, it doesn't actually appear to be
+// necessary, as long as the wait loop is very small (in terms of machine
+// code instruction count).  In testing, Erik has found that a flash-resident
+// version of the code is stable, and further found (by testing combinations
+// of cache control settings via the platform control register, MCM_PLACR)
+// that the stability comes from the loop fitting into CPU cache, which
+// allows the loop to execute without any fetches taking place.  Even so,
+// I'm keeping the RAM version, out of an abundance of caution: just in
+// case there are any rare or oddball conditions (interrupt timing, say) 
+// where the cache trick breaks.  Putting the code in RAM seems pretty
+// much guaranteed to work, whereas the cache trick seems somewhat to be
+// relying on a happy accident, and I personally don't know the M0+ 
+// architecture well enough to be able to convince myself that it really
+// will work under all conditions.  There doesn't seem to be any benefit
+// to not using the assembler, either, as it's very simple code and takes
+// up little RAM (about 40 bytes).
+
 
 #include "FreescaleIAP.h"
- 
+
 //#define IAPDEBUG
 
 // assembly interface
 extern "C" {
-    void iapEraseSector(FTFA_Type *ftfa, uint32_t address);
-    void iapProgramBlock(FTFA_Type *ftfa, uint32_t address, const void *src, uint32_t length);
+    // Execute the current FTFA command and wait for completion.
+    // This is an assembler implementation that runs entirely in RAM,
+    // to ensure strict compliance with the prohibition on reading
+    // flash (for instruction fetches or any other reason) during FTFA 
+    // execution.
+    void iapExecAndWait();
 }
 
-
- 
 enum FCMD {
     Read1s = 0x01,
     ProgramCheck = 0x02,
@@ -75,116 +63,47 @@
     VerifyBackdoor = 0x45
 };
 
-
-/* Check if an error occured 
-   Returns error code or Success*/
-static IAPCode check_error(void) 
-{
-    if (FTFA->FSTAT & FTFA_FSTAT_FPVIOL_MASK) {
-        #ifdef IAPDEBUG
-        printf("IAP: Protection violation\r\n");
-        #endif
-        return ProtectionError;
-    }
-    if (FTFA->FSTAT & FTFA_FSTAT_ACCERR_MASK) {
-        #ifdef IAPDEBUG
-        printf("IAP: Flash access error\r\n");
-        #endif
-        return AccessError;
-    }
-    if (FTFA->FSTAT & FTFA_FSTAT_RDCOLERR_MASK) {
-        #ifdef IAPDEBUG
-        printf("IAP: Collision error\r\n");
-        #endif
-        return CollisionError;
-    }
-    if (FTFA->FSTAT & FTFA_FSTAT_MGSTAT0_MASK) {
-        #ifdef IAPDEBUG
-        printf("IAP: Runtime error\r\n");
-        #endif
-        return RuntimeError;
-    }
-    #ifdef IAPDEBUG
-    printf("IAP: No error reported\r\n");
-    #endif
-    return Success;
-}
- 
-IAPCode FreescaleIAP::program_flash(int address, const void *src, unsigned int length) 
-{    
-    #ifdef IAPDEBUG
-    printf("IAP: Programming flash at %x with length %d\r\n", address, length);
-    #endif
-                
-    // presume success
-    IAPCode status = Success;
-
-    // I'm not 100% convinced this is 100% reliable yet.  So let's show
-    // some diagnostic lights while we're working.  If anyone sees any
-    // freezes, the lights that are left on at the freeze will tell us
-    // which step is crashing.
-    extern void diagLED(int,int,int);
-    
-    // Erase the sector(s) covered by the write.  Before writing, we must
-    // erase each sector that we're going to touch on the write.
-    for (uint32_t ofs = 0 ; ofs < length ; ofs += SECTOR_SIZE)
-    {
-        // Show RED on the first sector, GREEN on second, BLUE on third.  Each
-        // sector is 1K, so I don't think we'll need more than 3 for the 
-        // foreseeable future.  (RAM on the KL25Z is so tight that it will
-        // probably stop us from adding enough features to require more
-        // configuration variables than 3K worth.)
-        diagLED(ofs/SECTOR_SIZE == 0, ofs/SECTOR_SIZE == 1, ofs/SECTOR_SIZE == 2);
-        
-        // erase the sector
-        iapEraseSector(FTFA, address + ofs);
-    }
-        
-    // If the erase was successful, write the data.
-    if ((status = check_error()) == Success)
-    {
-        // show cyan while the write is in progress
-        diagLED(0, 1, 1);
-
-        // do the write
-        iapProgramBlock(FTFA, address, src, length);
-        
-        // purple when done
-        diagLED(1, 0, 1);
-        
-        // check again for errors
-        status = check_error();
-    }
-    
-    // return the result
-    return status;
-}
- 
-uint32_t FreescaleIAP::flash_size(void) 
+// Get the size of the flash memory on the device
+uint32_t FreescaleIAP::flashSize(void) 
 {
     uint32_t retval = (SIM->FCFG2 & 0x7F000000u) >> (24-13);
     if (SIM->FCFG2 & (1<<23))           // Possible second flash bank
         retval += (SIM->FCFG2 & 0x007F0000u) >> (16-13);
     return retval;
 }
- 
-/* Check if no flash boundary is violated
-   Returns true on violation */
-bool check_boundary(int address, unsigned int length) 
+
+// Check if an error occurred
+static FreescaleIAP::IAPCode checkError(void) 
 {
-    int temp = (address+length - 1) / SECTOR_SIZE;
-    address /= SECTOR_SIZE;
-    bool retval = (address != temp);
-    #ifdef IAPDEBUG
-    if (retval)
-        printf("IAP: Boundary violation\r\n");
-    #endif
-    return retval;
+    if (FTFA->FSTAT & FTFA_FSTAT_FPVIOL_MASK) {
+        #ifdef IAPDEBUG
+        printf("IAP: Protection violation\r\n");
+        #endif
+        return FreescaleIAP::ProtectionError;
+    }
+    if (FTFA->FSTAT & FTFA_FSTAT_ACCERR_MASK) {
+        #ifdef IAPDEBUG
+        printf("IAP: Flash access error\r\n");
+        #endif
+        return FreescaleIAP::AccessError;
+    }
+    if (FTFA->FSTAT & FTFA_FSTAT_RDCOLERR_MASK) {
+        #ifdef IAPDEBUG
+        printf("IAP: Collision error\r\n");
+        #endif
+        return FreescaleIAP::CollisionError;
+    }
+    if (FTFA->FSTAT & FTFA_FSTAT_MGSTAT0_MASK) {
+        #ifdef IAPDEBUG
+        printf("IAP: Runtime error\r\n");
+        #endif
+        return FreescaleIAP::RuntimeError;
+    }
+    return FreescaleIAP::Success;
 }
- 
-/* Check if address is correctly aligned
-   Returns true on violation */
-bool check_align(int address) 
+
+// check for proper address alignment
+static bool checkAlign(int address) 
 {
     bool retval = address & 0x03;
     #ifdef IAPDEBUG
@@ -193,4 +112,190 @@
     #endif
     return retval;
 }
- 
+
+// clear errors in the FTFA
+static void clearErrors()
+{
+    // wait for any previous command to complete    
+    while (!(FTFA->FSTAT & FTFA_FSTAT_CCIF_MASK)) ;
+
+    // clear the error bits
+    if (FTFA->FSTAT & (FTFA_FSTAT_ACCERR_MASK | FTFA_FSTAT_FPVIOL_MASK))
+        FTFA->FSTAT |= FTFA_FSTAT_ACCERR_MASK | FTFA_FSTAT_FPVIOL_MASK;
+}
+
+static FreescaleIAP::IAPCode eraseSector(int address) 
+{
+    #ifdef IAPDEBUG
+    printf("IAP: Erasing sector at %x\r\n", address);
+    #endif
+
+    // ensure proper alignment
+    if (checkAlign(address))
+        return FreescaleIAP::AlignError;
+    
+    // clear errors
+    clearErrors();
+    
+    // Set up the command
+    FTFA->FCCOB0 = EraseSector;
+    FTFA->FCCOB1 = (address >> 16) & 0xFF;
+    FTFA->FCCOB2 = (address >> 8) & 0xFF;
+    FTFA->FCCOB3 = address & 0xFF;
+    
+    // execute
+    iapExecAndWait();
+    
+    // check the result
+    return checkError();
+}
+
+static FreescaleIAP::IAPCode verifySectorErased(int address)
+{
+    // Always verify in whole sectors.  The
+    const unsigned int count = SECTOR_SIZE/4;
+
+    #ifdef IAPDEBUG
+    printf("IAP: Verify erased at %x, %d longwords (%d bytes)\r\n", address, count, count*4);
+    #endif
+    
+    if (checkAlign(address))
+        return FreescaleIAP::AlignError;
+
+    // clear errors
+    clearErrors();
+    
+    // Set up command
+    FTFA->FCCOB0 = Read1s;
+    FTFA->FCCOB1 = (address >> 16) & 0xFF;
+    FTFA->FCCOB2 = (address >> 8) & 0xFF;
+    FTFA->FCCOB3 = address & 0xFF;
+    FTFA->FCCOB4 = (count >> 8) & 0xFF;
+    FTFA->FCCOB5 = count & 0xFF;
+    FTFA->FCCOB6 = 0;
+
+    // execute    
+    iapExecAndWait();
+    
+    // check the result
+    FreescaleIAP::IAPCode retval = checkError();
+    if (retval == FreescaleIAP::RuntimeError) {
+        #ifdef IAPDEBUG
+        printf("IAP: Flash was not erased\r\n");
+        #endif
+        return FreescaleIAP::EraseError;
+    }
+    return retval;       
+}
+
+// Write one sector.  This always writes a full sector, even if the
+// requested length is greater or less than the sector size:
+//
+// - if len > SECTOR_SIZE, we write the first SECTOR_SIZE bytes of the data
+//
+// - if len < SECTOR_SIZE, we write the data, then fill in the rest of the
+//   sector with 0xFF bytes ('1' bits)
+//
+
+static FreescaleIAP::IAPCode writeSector(int address, const uint8_t *p, int len)
+{    
+    #ifdef IAPDEBUG
+    printf("IAP: Writing sector at %x with length %d\r\n", address, len);
+    #endif
+
+    // program the sector, one longword (32 bits) at a time
+    for (int ofs = 0 ; ofs < SECTOR_SIZE ; ofs += 4, address += 4, p += 4, len -= 4)
+    {
+        // clear errors
+        clearErrors();
+        
+        // Set up the command
+        FTFA->FCCOB0 = ProgramLongword;
+        FTFA->FCCOB1 = (address >> 16) & 0xFF;
+        FTFA->FCCOB2 = (address >> 8) & 0xFF;
+        FTFA->FCCOB3 = address & 0xFF;
+        
+        // Load the longword to write.  If we're past the end of the source
+        // data, write all '1' bits to the balance of the sector.
+        FTFA->FCCOB4 = len > 3 ? p[3] : 0xFF;
+        FTFA->FCCOB5 = len > 2 ? p[2] : 0xFF;
+        FTFA->FCCOB6 = len > 1 ? p[1] : 0xFF;
+        FTFA->FCCOB7 = len > 0 ? p[0] : 0xFF;
+        
+        // execute
+        iapExecAndWait();
+        
+        // check errors
+        FreescaleIAP::IAPCode status = checkError();
+        if (status != FreescaleIAP::Success)
+            return status;
+    }
+    
+    // no problems
+    return FreescaleIAP::Success;
+}
+
+// Program a block of memory into flash. 
+FreescaleIAP::IAPCode FreescaleIAP::programFlash(
+    int address, const void *src, unsigned int length) 
+{    
+    #ifdef IAPDEBUG
+    printf("IAP: Programming flash at %x with length %d\r\n", address, length);
+    #endif
+    
+    // presume success
+    FreescaleIAP::IAPCode status = FreescaleIAP::Success;
+    
+    // Show diagnostic LED colors while writing.  I'm finally convinced this
+    // is well and truly 100% reliable now, but I've been wrong before, so
+    // we'll keep this for now.  The idea is that if we freeze up, we'll at
+    // least know which stage we're at from the last color displayed.
+    extern void diagLED(int,int,int);
+    
+    // try a few times if we fail to verify
+    for (int tries = 0 ; tries < 5 ; ++tries)
+    {
+        // Do the write one sector at a time
+        int curaddr = address;
+        const uint8_t *p = (const uint8_t *)src;
+        int rem = (int)length;
+        for ( ; rem > 0 ; curaddr += SECTOR_SIZE, p += SECTOR_SIZE, rem -= SECTOR_SIZE)
+        {
+            // erase the sector (red LED)
+            diagLED(1, 0, 0);
+            if ((status = eraseSector(curaddr)) != FreescaleIAP::Success)
+                break;
+            
+            // verify that the sector is erased (yellow LED)
+            diagLED(1, 1, 0);
+            if ((status = verifySectorErased(curaddr)) != FreescaleIAP::Success)
+                break;
+            
+            // write the data (white LED)
+            diagLED(1, 1, 1);
+            if ((status = writeSector(curaddr, p, rem)) != FreescaleIAP::Success)
+                break;
+                
+            // back from write (purple LED)
+            diagLED(1, 0, 1);
+        }
+        
+        // if we didn't encounter an FTFA error, verify the write
+        if (status == FreescaleIAP::Success)
+        {
+            // Verify the write.  If it was successful, we're done.
+            if (memcmp((void *)address, src, length) == 0)
+                break;
+                
+            // We have a mismatch between the flash data and the source.
+            // Flag the error and go back for another attempt.
+            status = FreescaleIAP::VerifyError;
+        }
+    }
+    
+    __enable_irq();
+        
+    // return the result
+    return status;
+}
+