diff options
Diffstat (limited to 'cores/arduino')
| -rw-r--r-- | cores/arduino/CDC.cpp | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/cores/arduino/CDC.cpp b/cores/arduino/CDC.cpp index 7f33a6e..6d3929e 100644 --- a/cores/arduino/CDC.cpp +++ b/cores/arduino/CDC.cpp @@ -101,13 +101,26 @@ bool WEAK CDC_Setup(Setup& setup) if (CDC_SET_CONTROL_LINE_STATE == r) { _usbLineInfo.lineState = setup.wValueL; + // auto-reset into the bootloader is triggered when the port, already // open at 1200 bps, is closed. this is the signal to start the watchdog // with a relatively long period so it can finish housekeeping tasks // like servicing endpoints before the sketch ends - if (0 != _usbLineInfo.lineState && 1200 == _usbLineInfo.dwDTERate) { + + // We check DTR state to determine if host port is open (bit 0 of lineState). + // Serial1.print(">"); Serial1.println(_usbLineInfo.lineState, HEX); + if ((_usbLineInfo.lineState & 0x01) == 0 && _usbLineInfo.dwDTERate == 1200) { *(uint16_t *)0x0A00 = 0x7777; wdt_enable(WDTO_250MS); + } else { + // Most OSs do some intermediate steps when configuring ports and DTR can + // twiggle more than once before stabilizing. + // To avoid spurious resets we set the watchdog to 250ms and eventually + // cancel if DTR goes back high. + + wdt_disable(); + wdt_reset(); + *(uint16_t *)0x0A00 = 0x0; } return true; } @@ -202,4 +215,4 @@ size_t Serial_::write(uint8_t c) Serial_ Serial; #endif -#endif /* if defined(USBCON) */
\ No newline at end of file +#endif /* if defined(USBCON) */ |