experimental support for MTP

README.md

@@ -9,6 +9,7 @@ This is a fork of [fwachsmuth/Synkino](https://github.com/fwachsmuth/Synkino) wi
 * SynkinoLC uses only a few off-the-shelf components to make assembly as straightforward as possible. No SMD soldering is required.
 * The firmware has been optimized to fit the 62K flash of the affordable but powerful Teensy LC microcontroller board (with a few limitations - see below). Teensy 3.2 is also supported.
 * Unlike the original Synkino, SynkinoLC is not designed for battery operation. Use any micro-USB phone charger as a power supply unit.
+* When connected to a PC/Mac via USB you'll have direct access to SynkinoLC's SD card via MTP (Teensy 3.2 only).
 
 Most parts of [Friedemann's manual for the original Synkino](https://www.filmkorn.org/synkino-instruction-manual/?lang=en) apply for SynkinoLC as well.
 
@@ -21,6 +22,7 @@ When assembling SynkinoLC, you can chose between using a Teensy LC or Teensy 3.2
 * You can store settings for "only" 7 projectors (vs 15 on Teensy 3.2).
 * The USB stack has been omitted - you can't use debugging by means of USBSerial. You can, however, use the Teensy's HW serial interface (TX on pin 1, 31250 baud).
 * SdFat is running in low-mem mode (no support for exFAT, limited to 32GB cards and 64 character filenames).
+* No MTP access to the SD card.
 
 Neither of these limitations should have a significant impact on the usability of SynkinoLC.
 

platformio.ini

@@ -11,17 +11,16 @@
 [env]
 platform = teensy
 framework = arduino
+extra_scripts =
+	pre:patches.py
+
+[env:teensyLC]
 lib_deps =
 	olikraus/U8g2 @ ^2.34.4
 	adafruit/Adafruit VS1053 Library @ 1.2.1
 	https://github.com/luni64/EncoderTool
-	alexiii/incbin @ ^0.1.2
 	luni64/TeensyTimerTool @ ^0.4.4
 	dlloydev/QuickPID @ ^3.1.2
-extra_scripts =
-	pre:patches.py
-
-[env:teensyLC]
 board = teensylc
 build_flags =
 	-D TEENSY_OPT_SMALLEST_CODE_LTO
@@ -34,8 +33,17 @@ build_flags =
 	-D U8G2_WITHOUT_FONT_ROTATION
 
 [env:teensy31]
+lib_deps =
+	olikraus/U8g2 @ ^2.34.4
+	adafruit/Adafruit VS1053 Library @ 1.2.1
+	https://github.com/luni64/EncoderTool
+	luni64/TeensyTimerTool @ ^0.4.4
+	dlloydev/QuickPID @ ^3.1.2
+	alexiii/incbin @ ^0.1.2
+	https://github.com/KurtE/MTP_Teensy
 board = teensy31
 build_flags =
 	-D INC_PATCHES
 	-D SERIALDEBUG
 	-D U8X8_NO_HW_I2C
+	-D USB_MTPDISK_SERIAL

src/audio.cpp

@@ -18,6 +18,11 @@ extern PolledEncoder enc;
   INCBIN(Patch, "patches.053");
 #endif
 
+// Use MTP disk?
+#if defined USB_MTBDISK || defined USB_MTPDISK_SERIAL
+  #include <MTP_Teensy.h>
+#endif
+
 // macros for time conversion
 #define SECS_PER_MIN            (60UL)
 #define SECS_PER_HOUR           (3600UL)
@@ -221,6 +226,9 @@ bool Audio::selectTrack() {
   beeTimer.stop();
   while (state != QUIT) {
     yield();
+    #if defined USB_MTBDISK || defined USB_MTPDISK_SERIAL
+      MTP.loop();
+    #endif
 
     switch (state) {
     case CHECK_FOR_LEADER:

src/main.cpp

@@ -21,6 +21,13 @@ using namespace EncoderTool;
 #include "pins.h"         // pin definitions
 #include "menus.h"        // menu definitions, positions of menu items
 
+// Use MTP disk?
+#if defined USB_MTBDISK || defined USB_MTPDISK_SERIAL
+  #include <SD.h>
+  #include <MTP_Teensy.h>
+  #define CS_SD VS1053_SDCS
+#endif
+
 // Declaration of functions
 // See https://docs.platformio.org/en/latest/faq/ino-to-cpp.html
 void dimDisplay(bool);
@@ -96,6 +103,11 @@ void setup(void) {
   }
   boardRevision[18] = musicPlayer.getRevision();
 
+  // initialize MTP filesystem
+  #if defined USB_MTBDISK || defined USB_MTPDISK_SERIAL
+    MTP.addFilesystem(SD, "SynkinoLC Storage");
+  #endif
+
   projector.loadLast();
 
   PRINTLN("Startup complete.\n");
@@ -222,6 +234,9 @@ void breathe(bool doBreathe) {
 // This overwrites the weak function in u8x8_debounce.c
 uint8_t u8x8_GetMenuEvent(u8x8_t *u8x8) {
     yield();
+    #if defined USB_MTBDISK || defined USB_MTPDISK_SERIAL
+      MTP.loop();
+    #endif
 
     if (enc.valueChanged()) {
       buzzer.playClick();                         // feedback sound