Merge pull request #22 from anarkiwi/pthru

Add configuration for transparent mode.

README.md

@@ -180,17 +180,17 @@ The C64 can send Vessel a command, by sending byte 0xFD (not used by MIDI),
 and then a command, and then a fixed number of data bytes (depending on the
 command - unless otherwise specified, a command is followed by 0 data bytes).
 
-By default, NMI on external input is off, all MIDI channels are masked and
-all status messages will be masked (no MIDI messages will be sent to the C64)
-and MIDI through is disabled.
+By default, transparent mode is off, NMI on external input is off, all MIDI channels
+are masked and all status messages will be masked (no MIDI messages will be sent
+to the C64) and MIDI through is disabled.
 
 |byte|command |arg bytes|description
 |----|------------|---------|--------------------------------------------------------------------------
 |0x00|Reset | |Vessel will reset to default config.
 |0x01|Purge | |Vessel will discard any buffered data.
 |0x02|Panic | |Reserved for future implementation. Send all notes off on all channels.
 |0x03|Version | |Vessel will return a version string (currently C64 screen code "vessel00").
-|0x04|Config |CF |CF bit 0 enables NMI, bit 1 enables MIDI through.
+|0x04|Config |CF |CF bit 0 enables NMI, bit 1 enables MIDI through, bit 2 enables transparent (no MIDI parsing) mode.
 |0x05|Channel mask|HH LL |High byte (HH), low byte (LL) for channels 1 to 16.
 |0x06|Status mask |HH LL |High byte (HH), low byte (LL) for channel-less messages F0 to FF.
 |0x07|Control mask|CM |MSB unused, 3 high bits command mask, 4 low bits channel.

vessel.ino

@@ -108,6 +108,7 @@ volatile byte outBufWritePtr = 0;
 volatile byte *outBufReadPtr = outBuf;
 volatile IsrModeEnum isrMode = ISR_INPUT;
 volatile bool nmiEnabled = false;
+volatile bool transparent = false;
 volatile bool status = false;
 volatile uint16_t receiveChannelMask = 0;
 volatile uint16_t receiveStatusMask = 0;
@@ -347,7 +348,12 @@ inline bool drainOutBuf() {
  flagPin.write(LOW);
  return true;
  } else if (uartRxready()) {
- fs.set(uartRead());
+ if (transparent) {
+ NMI_WRAP(fs.write(uartRead()));
+ flagPin.write(LOW);
+ } else {
+ fs.set(uartRead());
+ }
  blink();
  return true;
  }
@@ -416,6 +422,7 @@ inline void resetCmd() {
  receiveStatusMask = 0;
  memset(receiveCommandMask, 0, sizeof(receiveCommandMask));
  nmiEnabled = false;
+ transparent = false;
  MIDI.turnThruOff();
  purgeCmd();
 }
@@ -436,6 +443,7 @@ inline void configFlagsCmd() {
  } else {
  MIDI.turnThruOff();
  }
+ transparent = configFlags & 4;
 }
 
 inline uint16_t get2bMask() {