C515C_9711 Datasheet, PDF (115/268 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Components
C515C
Timer 1
Overflow
Baud
Rate
f _OSC
Generator
(SRELH
SRELL)
÷6
ADCON0.7
SCON.7
(BD)
SCON.6
(SM0/
0
1
Mode 1
SM1)
Mode 3
÷2
Mode 2
Mode 0
Only one mode
can be selected
Note: The switch configuration shows the reset state.
PCON.7
(SMOD)
0
Baud
1
Rate
Clock
MCS02733
Figure 6-29
Baud Rate Generation for the Serial Port
Depending on the programmed operating mode different paths are selected for the baud rate clock
generation. Figure 6-29 shows the dependencies of the serial port 0 baud rate clock generation
from the two control bits and from the mode which is selected in the special function register
S0CON.
6.3.3.1 Baud Rate in Mode 0
The baud rate in mode 0 is fixed to :
Mode 0 baud rate = ^{oscillator frequency}
6
6.3.3.2 Baud Rate in Mode 2
The baud rate in mode 2 depends on the value of bit SMOD in special function register PCON. If
SMOD = 0 (which is the value after reset), the baud rate is 1/32 of the oscillator frequency. If SMOD
= 1, the baud rate is 1/16 of the oscillator frequency.
2 ^SMOD
Mode 2 baud rate =
x oscillator frequency
32
Semiconductor Group
6-52
1997-11-01