Merge pull request #17 from anarkiwi/fio

 Don't drain transmit buffer right after MIDI receive activity to avoid a slow I/O direction change

README.md

@@ -197,7 +197,10 @@ Upgrading firmware
 ------------------
 
 The Arduino IDE can be used to reflash Vessel via the onboard USB-C port.
-You should select the right port in the Tools menu before uploading.
+You should select the right port in the Tools menu before uploading
+(Vessel will show as an Arduino Due, native port). You will also need
+the "MIDI Library" (by Francois Best) installed, via Tools/Manage Libraries,
+and support for SAM boards installed (Tools/Board Manager).
 
 NOTE: you will need to add the following to to WInterrupts.c:
 
@@ -208,7 +211,8 @@ On Linux this can be located with the following command.
  josh@vek-x:~$ find .arduino15 -name WInterrupts.c
  .arduino15/packages/arduino/hardware/sam/1.6.12/cores/arduino/WInterrupts.c
 
-If you will upgrade the IDE you will have to change this file again.
+If you will upgrade the IDE you will have to change this file again. Be careful
+to change the WInterrupts.c file in the "sam" directory, NOT the "avr" directory.
 
 
 Vesselmon

vessel.ino

@@ -335,19 +335,21 @@ inline bool inBufWaiting() {
 
 inline void drainInBuf() {
  // Avoid buffering, ensure we write direct to UART without waiting.
- if (uartTxready() && inBufWaiting()) {
+ if (inBufWaiting() && uartTxready()) {
  uartWrite(inBuf[++inBufWritePtr]);
  blink();
  }
 }
 
-inline void drainOutBuf() {
+inline bool drainOutBuf() {
  if (uartRxready()) {
  fs.set(uartRead());
  MIDI.read();
  flagPin.write(LOW);
  blink();
+ return true;
  }
+ return false;
 }
 
 inline void resetWritePtrs() {
@@ -361,8 +363,9 @@ inline void inputMode() {
  isrMode = ISR_INPUT;
  interrupts();
  while (inInputMode()) {
- drainOutBuf();
- drainInBuf();
+ if (!drainOutBuf()) {
+ drainInBuf();
+ }
  }
 }