I am porting code from 87C576 to 87c591 chip. On the 576 chip they used timer 2 as the baud rate generator for serial 0. The 591 chip has many differences due to the CAN capability that was added. Here is the way the 576 chip was set up.
#define SCON_INIT 0x50 /* SERIAL CONTROL REGISTER */ /* BIT 0 = 0 RI END REC FLAG */ /* BIT 1 = 0 TI END XMIT FLAG */ /* BIT 2 = 0 RB8 9 TH BIT REC */ /* BIT 3 = 0 TB8 9 TH BIT XMIT */ /* BIT 4 = 1 REN REC DISABLED */ /* BIT 5 = 0 SM2 MULTI DISABLED */ /* BIT 6 = 1 SM1 SEL MODE */ /* BIT 7 = 0 SM0 SEL MODE */ #define TMOD_INIT 0x11 /* TIMER MODE CONTROL REGISTER /* BIT 0 = 1 M0 TIMER 0 MODE */ /* BIT 1 = 0 M1 SELECT */ /* BIT 2 = 0 C/T0 CLOCK CONTROL */ /* BIT 3 = 0 GATE TR0/INT0 CONTROL */ /* BIT 4 = 1 M0 TIMER 1 MODE */ /* BIT 5 = 0 M1 SELECT */ /* BIT 6 = 0 C/T1 CLOCK CONTROL */ /* BIT 7 = 0 GATE TR0/INT0 CONTROL */ #define TCON_INIT 0x50 /* TIMER CONTROL REGISTER */ /* BIT 0 = 0 IT0 EXT 0 DETECT MODE */ /* BIT 1 = 0 IE0 EXT INT 0 FLAG */ /* BIT 2 = 0 IT1 EXT 1 DETECT MODE */ /* BIT 3 = 0 IE1 EXT INT 1 FLAG */ /* BIT 4 = 1 TR0 START/STOP */ /* BIT 5 = 0 TF0 TIMER 0 INT FLAG */ /* BIT 6 = 1 TR1 START/STOP */ /* BIT 7 = 0 TF1 TIMER 1 INT FLAG */
#define T2CON_INIT 0x34 /* TIMER 2 CONTROL REGISTER */ /* BIT 0 = 0 CP/RL2 CAPTURE/RELOAD FLAG */ /* BIT 1 = 0 C/T2 TIMER/COUNTER SEL */ /* BIT 2 = 1 TR2 START/STOP */ /* BIT 3 = 0 EXEN2 TIMER ENABLE FLAG */ /* BIT 4 = 1 TLCK TRANSMIT CLOCK FLAG */ /* BIT 5 = 1 RCLK RECEIVE CLOCK FLAG */ /* BIT 6 = 0 EXF2 TIMER 2 EXT FLAG */ /* BIT 7 = 0 TF2 TIMER OVERFLOW FLAG */
Here is how Timer 2 is initialized to act as the baud rate generator.
/* Timer 2 setup as baud rate generator */ RCAP2L = TL2 = LOW_BYTE(BAUD_COUNT); RCAP2H = TH2 = HIGH_BYTE(BAUD_COUNT);
Looking at the data sheet for the 591, it is not clear at all if the same setup can be used. Timer 1 and 0 are being used for other things.
Does anyone know if Timer 2 in the 591 can be used in the same way.
steve