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.

--- a/main.cpp	Wed Oct 21 21:53:07 2015 +0000
+++ b/main.cpp	Thu Dec 03 07:34:57 2015 +0000
@@ -264,6 +264,7 @@
 #include "FreescaleIAP.h"
 #include "crc32.h"
 #include "TLC5940.h"
+#include "74HC595.h"
 #include "config.h"
@@ -421,6 +422,19 @@
     virtual void set(float val) { }
+// Active Low out.  For any output marked as active low, we layer this
+// on top of the physical pin interface.  This simply inverts the value of
+// the output value, so that 1.0 means fully off and 0.0 means fully on.
+class LwInvertedOut: public LwOut
+    LwInvertedOut(LwOut *o) : out(o) { }
+    virtual void set(float val) { out->set(1.0 - val); }
+    LwOut *out;
 #if TLC5940_NCHIPS
@@ -442,21 +456,12 @@
     virtual void set(float val)
         if (val != prv)
-           tlc5940.set(idx, (int)(val * 4095));
+           tlc5940.set(idx, (int)((prv = val) * 4095));
     int idx;
     float prv;
-// Inverted voltage version of TLC5940 class (Active Low - logical "on"
-// is represented by 0V on output)
-class Lw5940OutInv: public Lw5940Out
-    Lw5940OutInv(int idx) : Lw5940Out(idx) { }
-    virtual void set(float val) { Lw5940Out::set(1.0 - val); }
 // No TLC5940 chips are attached, so we shouldn't encounter any ports
 // in the map marked for TLC5940 outputs.  If we do, treat them as unused.
@@ -466,13 +471,58 @@
     Lw5940Out(int idx) { }
-class Lw5940OutInv: public Lw5940Out
+// dummy tlc5940 interface
+class Dummy5940
+    void start() { }
+Dummy5940 tlc5940;
+#endif // TLC5940_NCHIPS
+#if HC595_NCHIPS
+// 74HC595 interface object.  Set this up with the port assignments in
+// config.h.
+HC595 hc595(HC595_NCHIPS, HC595_SIN, HC595_SCLK, HC595_LATCH, HC595_ENA);
+// LwOut class for 74HC595 outputs.  These are simple digial outs.
+// The 'idx' value in the constructor is the output index in the
+// daisy-chained 74HC595 array.  0 is output #0 on the first chip,
+// 1 is #1 on the first chip, 7 is #7 on the first chip, 8 is
+// #0 on the second chip, etc.
+class Lw595Out: public LwOut
-    Lw5940OutInv(int idx) : Lw5940Out(idx) { }
+    Lw595Out(int idx) : idx(idx) { prv = -1; }
+    virtual void set(float val)
+    {
+        if (val != prv)
+           hc595.set(idx, (prv = val) == 0.0 ? 0 : 1);
+    }
+    int idx;
+    float prv;
-#endif // TLC5940_NCHIPS
+#else // HC595_NCHIPS
+// No 74HC595 chips are attached, so we shouldn't encounter any ports
+// in the map marked for these outputs.  If we do, treat them as unused.
+class Lw595Out: public LwUnusedOut
+    Lw595Out(int idx) { }
+// dummy placeholder class
+class DummyHC595 
+    void init() { }
+    void update() { }
+DummyHC595 hc595;
+#endif // HC595_NCHIPS
 // Default LedWiz mode - using on-board GPIO ports.  In this mode, we
@@ -496,16 +546,6 @@
     float prv;
-// Inverted voltage PWM-capable GPIO port.  This is the Active Low
-// version of the port - logical "on" is represnted by 0V on the
-// GPIO pin.
-class LwPwmOutInv: public LwPwmOut
-    LwPwmOutInv(PinName pin) : LwPwmOut(pin) { }
-    virtual void set(float val) { LwPwmOut::set(1.0 - val); }
 // LwOut class for a Digital-Only (Non-PWM) GPIO port
 class LwDigOut: public LwOut
@@ -520,14 +560,6 @@
     float prv;
-// Inverted voltage digital out
-class LwDigOutInv: public LwDigOut
-    LwDigOutInv(PinName pin) : LwDigOut(pin) { }
-    virtual void set(float val) { LwDigOut::set(1.0 - val); }
 // Array of output physical pin assignments.  This array is indexed
 // by LedWiz logical port number - lwPin[n] is the maping for LedWiz
 // port n (0-based).  If we're using GPIO ports to implement outputs,
@@ -551,19 +583,30 @@
     // Figure out how many outputs we have.  We always have at least
     // 32 outputs, since that's the number fixed by the original LedWiz
-    // protocol.  If we're using TLC5940 chips, we use our own custom
-    // extended protocol that allows for many more ports.  In this case,
-    // we have 16 outputs per TLC5940, plus any assigned to GPIO pins.
+    // protocol.  If we're using TLC5940 chips, each chip provides 16
+    // outputs.  Likewise, each 74HC595 provides 8 outputs.
-    // start with 16 ports per TLC5940
-    numOutputs = TLC5940_NCHIPS * 16;
+    // start with 16 ports per TLC5940 and 8 per 74HC595
+    numOutputs = TLC5940_NCHIPS*16 + HC595_NCHIPS*8;
-    // add outputs assigned to GPIO pins in the LedWiz-to-pin mapping
+    // add outputs explicitly assigned to GPIO pins or not connected
     int i;
     for (i = 0 ; i < countof(ledWizPortMap) ; ++i)
-        if (ledWizPortMap[i].pin != NC)
+        switch (ledWizPortMap[i].typ)
+        {
+        case DIG_GPIO:
+        case PWM_GPIO:
+        case NO_PORT:
+            // count an explicitly GPIO port
+            break;
+        default:
+            // DON'T count TLC5940 or 74HC595 ports, as we've already
+            // counted all of these above
+            break;
+        }
     // always set up at least 32 outputs, so that we don't have to
@@ -582,69 +625,79 @@
     char *tlcasi = new char[TLC5940_NCHIPS*16+1];
     memset(tlcasi, 0, TLC5940_NCHIPS*16);
-    // assign all pins from the port map in config.h
+    // likewise for the 74HC595 ports
+    char *hcasi = new char[HC595_NCHIPS*8+1];
+    memset(hcasi, 0, HC595_NCHIPS*8);
+    // assign all pins from the explicit port map in config.h
     for (i = 0 ; i < countof(ledWizPortMap) ; ++i)
-        // Figure out which type of pin to assign to this port:
-        //
-        // - If it has a valid GPIO pin (other than "NC"), create a PWM
-        //   or Digital output pin according to the port type.
-        //
-        // - If the pin has a TLC5940 port number, set up a TLC5940 port.
-        //
-        // - Otherwise, the pin is unconnected, so set up an unused out.
-        //
-        PinName p = ledWizPortMap[i].pin;
+        int pin = ledWizPortMap[i].pin;
+        LWPortType typ = ledWizPortMap[i].typ;
         int flags = ledWizPortMap[i].flags;
-        int tlcPortNum = ledWizPortMap[i].tlcPortNum;
-        int isPwm = flags & PORT_IS_PWM;
         int activeLow = flags & PORT_ACTIVE_LOW;
-        if (p != NC)
+        switch (typ)
-            // This output is a GPIO - set it up as PWM or Digital, and 
-            // active high or low, as marked
-            if (isPwm)
-                lwPin[i] = activeLow ? new LwPwmOutInv(p) : new LwPwmOut(p);
-            else
-                lwPin[i] = activeLow ? new LwDigOutInv(p) : new LwDigOut(p);
+        case DIG_GPIO:
+            lwPin[i] = new LwDigOut((PinName)pin);
+            break;
+        case PWM_GPIO:
+            // PWM GPIO port
+            lwPin[i] = new LwPwmOut((PinName)pin);
+            break;
+        case TLC_PORT:
+            // TLC5940 port (note that the nominal pin in the map is 1-based, so we
+            // have to decrement it to get the real pin index)
+            lwPin[i] = new Lw5940Out(pin-1);
+            tlcasi[pin-1] = 1;
+            break;
+        case HC595_PORT:
+            // 74HC595 port (the pin in the map is 1-based, so decrement it to get the 
+            // real pin index)
+            lwPin[i] = new Lw595Out(pin-1);
+            hcasi[pin-1] = 1;
+            break;
+        default:
+            lwPin[i] = new LwUnusedOut();
+            break;
-        else if (tlcPortNum != 0)
-        {
-            // It's a TLC5940 port.  Note that the port numbering in the map
-            // starts at 1, but internally we number the ports starting at 0,
-            // so subtract one to get the correct numbering.
-            lwPin[i] = activeLow ? new Lw5940OutInv(tlcPortNum-1) : new Lw5940Out(tlcPortNum-1);
-            // mark this port as used, so that we don't reassign it when we
-            // fill out the remaining unassigned ports
-            tlcasi[tlcPortNum-1] = 1;
-        }
-        else
-        {
-            // it's not a GPIO or TLC5940 port -> it's not connected
-            lwPin[i] = new LwUnusedOut();
-        }
+        // if it's Active Low, layer an inverter
+        if (activeLow)
+            lwPin[i] = new LwInvertedOut(lwPin[i]);
+        // turn it off initially      
-    // find the next unassigned tlc port
-    int tlcnxt;
+    // If we haven't assigned all of the LedWiz ports to physical pins,
+    // fill out the unassigned LedWiz ports with any unassigned TLC5940
+    // pins, then with any unassigned 74HC595 ports.
+    int tlcnxt, hcnxt;
     for (tlcnxt = 0 ; tlcnxt < TLC5940_NCHIPS*16 && tlcasi[tlcnxt] ; ++tlcnxt) ;
-    // assign any remaining pins
+    for (hcnxt = 0 ; hcnxt < HC595_NCHIPS*8 && hcasi[hcnxt] ; ++hcnxt) ;
     for ( ; i < numOutputs ; ++i)
         // If we have any more unassigned TLC5940 outputs, assign this LedWiz
-        // port to the next available TLC5940 output.  Otherwise make it
-        // unconnected.
+        // port to the next available TLC5940 output, or the next 74HC595 output
+        // if we're out of TLC5940 outputs.  Leave it unassigned if there are
+        // no more unassigned ports of any type.
         if (tlcnxt < TLC5940_NCHIPS*16)
-            // we have a TLC5940 output available - assign it
+            // assign this available TLC5940 pin, and find the next unused one
             lwPin[i] = new Lw5940Out(tlcnxt);
-            // find the next unassigned TLC5940 output, for the next port
             for (++tlcnxt ; tlcnxt < TLC5940_NCHIPS*16 && tlcasi[tlcnxt] ; ++tlcnxt) ;
+        else if (hcnxt < HC595_NCHIPS*8)
+        {
+            // assign this available 74HC595 pin, and find the next unused one
+            lwPin[i] = new Lw595Out(hcnxt);
+            for (++hcnxt ; hcnxt < HC595_NCHIPS*8 && hcasi[hcnxt] ; ++hcnxt) ;
+        }
             // no more ports available - set up this port as unconnected
@@ -652,8 +705,9 @@
-    // done with the temporary TLC5940 port assignment list
+    // done with the temporary TLC5940 and 74HC595 port assignment lists
     delete [] tlcasi;
+    delete [] hcasi;
 // LedWiz output states.
@@ -840,8 +894,11 @@
     // isn't running, turn it on
     if (pulse)
         wizPulseTimer.attach(wizPulse, WIZ_PULSE_TIME_BASE);
+    // flush changes to 74HC595 chips, if attached
+    hc595.update();
 // ---------------------------------------------------------------------------
 // Button input
@@ -1321,7 +1378,9 @@
     // has been properly initialized
     uint32_t checksum;
-    // signature value
+    // signature and version, to verify that we saved the config
+    // data to flash on a past run (as opposed to uninitialized
+    // data from a firmware update)
     static const uint32_t SIGNATURE = 0x4D4A522A;
     static const uint16_t VERSION = 0x0003;
@@ -1339,8 +1398,10 @@
     void save(FreescaleIAP &iap, int addr)
         // update the checksum and structure size
+        d.sig = SIGNATURE;
+        d.vsn = VERSION;
+ = sizeof(NVM);
         checksum = CRC32(&d, sizeof(d));
- = sizeof(NVM);
         // erase the sector
@@ -1483,6 +1544,9 @@
     // restore default LedWiz flash rate
     wizSpeed = 2;
+    // flush changes to hc595, if applicable
+    hc595.update();
 // ---------------------------------------------------------------------------
@@ -1674,18 +1738,6 @@
     // we're not connected/awake yet
     bool connected = false;
     time_t connectChangeTime = time(0);
-#if TLC5940_NCHIPS
-    // start the TLC5940 clock
-    for (int i = 0 ; i < numOutputs ; ++i) lwPin[i]->set(1.0);
-    tlc5940.start();
-    // enable power to the TLC5940 opto/LED outputs
-# ifdef TLC5940_PWRENA
-    DigitalOut tlcPwrEna(TLC5940_PWRENA);
-    tlcPwrEna = 1;
-# endif
     // initialize the LedWiz ports
@@ -1693,6 +1745,13 @@
     // initialize the button input ports
+    // start the TLC5940 clock, if present
+    tlc5940.start();
+    // enable the 74HC595 chips, if present
+    hc595.init();
+    hc595.update();
     // we don't need a reset yet
     bool needReset = false;
@@ -1707,19 +1766,14 @@
     NVM *flash = (NVM *)flash_addr;
     NVM cfg;
-    // check for valid flash
-    bool flash_valid = flash->valid();
     // if the flash is valid, load it; otherwise initialize to defaults
-    if (flash_valid) {
+    if (flash->valid()) {
         memcpy(&cfg, flash, sizeof(cfg));
         printf("Flash restored: plunger cal=%d, min=%d, zero=%d, max=%d\r\n", 
             cfg.d.plungerCal, cfg.d.plungerMin, cfg.d.plungerZero, cfg.d.plungerMax);
     else {
         printf("Factory reset\r\n");
-        cfg.d.sig = cfg.SIGNATURE;
-        cfg.d.vsn = cfg.VERSION;
         cfg.d.plungerCal = 0;
         cfg.d.plungerMin = 0;        // assume we can go all the way forward...
         cfg.d.plungerMax = npix;     // ...and all the way back
@@ -1964,6 +2018,7 @@
                     // update the physical outputs
+                    hc595.update();
                     // reset the PBA counter
                     pbaIdx = 0;
@@ -2073,6 +2128,9 @@
                         // set the output
+                    // update 74HC595 outputs, if attached
+                    hc595.update();
@@ -2107,6 +2165,7 @@
                     if (pbaIdx == 24)
+                        hc595.update();
                         pbaIdx = 0;
@@ -2170,9 +2229,6 @@
                 // save the updated configuration
                 cfg.d.plungerCal = 1;
       , flash_addr);
-                // the flash state is now valid
-                flash_valid = true;
             else if (calBtnState != 3)