SIR
SIR = target;
SPEEDCASE( 2400, SIR, 0xbf);
SPEEDCASE( 9600, SIR, 0x2f);
SPEEDCASE( 19200, SIR, 0x17);
SPEEDCASE( 38400, SIR, 0x0b);
SPEEDCASE( 57600, SIR, 0x07);
SPEEDCASE( 115200, SIR, 0x03);