interrupt called getc() | Piclist

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Hello, I've just spent a *very* long time fooling around with a rs232 asyncronous reciever on an RB interrupt. The interrupt looks something like this: #int_RB void RxChar() // input through RB7 { INTCON.RBIE=0; RCREG_X=fgetc(MCP_rs232); restart_wdt(); INTCON.RBIF=0; INTCON.RBIE=1; INTCON.GIE=1; } The fastest I can get the baud rate without getting errors is 19200 on an 11059200 Hz clock. An example is recieving A2 when in fact it is a 44. And a 8A when in fact it is a 15 (all in hex). Heres what i suspect: In rs232, LSB is sent first. 0x44 = 0b01000100 0xA2 = 0b10100010 When in rs232 the order is then flipped so 0b01000100 -> 00100010... comparing this to 0xA2 as it would appear over a rs232 line is 01000101. 01000101 ... the A2 in reverse order (what i got) 00100010 ... the 44 in reverse order (what i expected) It looks rather simple to fix (just shift it right and throw on a zero), but is there a better way to fix this problem without creating my own getc()? Im not sure what would happen if the rs232 value had a leading 1, ie 10110101... probably blow up. BTW: the 15 and 8A works the exact same way. I'm also thinking that if i were to increase my clock speed (while keeping it a nice multiple of 9600) then that might also remedy the problem. Chris

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Discussion Groups | Piclist | interrupt called getc()

interrupt called getc() - sirtiffguy - Nov 29 4:16:00 2004