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Implement XON/XOFF handling for the serial read queue. The former 

solution was less computing intensive, but failed when the GCode
interpreter couldn't keep up with the incoming stream, e.g. when
handling a lot of tiny moves.

The old implementation is still in place but somewhat redundant
now, so stay tuned ...

Oh, and G4 Dwell works now as well.
This commit is contained in:
Markus Hitter 2010-10-05 20:22:09 +02:00
parent 5e1ce4ec96
commit a438a3fa2f
1 changed files with 19 additions and 0 deletions
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19
serial.c
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@ -88,6 +88,15 @@ ISR(USART0_RX_vect)
// not reading the character makes the interrupt logic to swamp us with retries, so better read it and throw it away
trash = UDR0;
}
#ifdef XONXOFF
if (flowflags & FLOWFLAG_STATE_XON && buf_canread(rx) >= BUFSIZE - 16) {
// the buffer has only 16 free characters left, so send an XOFF
// more characters might come in until the XOFF takes effect
flowflags = FLOWFLAG_SEND_XOFF | FLOWFLAG_STATE_XON;
UCSR0B |= MASK(UDRIE0);
}
#endif
}
#ifdef USART_UDRE_vect
@ -125,9 +134,19 @@ uint8_t serial_rxchars()
uint8_t serial_popchar()
{
uint8_t c = 0;
// it's imperative that we check, because if the buffer is empty and we pop, we'll go through the whole buffer again
if (buf_canread(rx))
buf_pop(rx, c);
#ifdef XONXOFF
if ((flowflags & FLOWFLAG_STATE_XON) == 0 && buf_canread(rx) <= 16) {
// the buffer has (BUFSIZE - 16) free characters again, so send an XON
flowflags = FLOWFLAG_SEND_XON;
UCSR0B |= MASK(UDRIE0);
}
#endif
return c;
}