C508_01 Datasheet, PDF (172/267 Pages) Infineon Technologies AG – 8-Bit CMOS Microcontroller

C508
On-Chip Peripheral Components
Figure 6-41 shows the configuration for the baudrate generation of the serial port.
Timer 1 Overflow
ADCON0.7
(BD)
Baudrate
0
2f_OSC
Generator
(SRELH
1
SRELL)
SCON.7/
SCON.6
(SM0/SM1)
Mode 1
Mode 3
÷2
Mode 2
Mode 0
Only one mode
÷6
can be selected
PCON.7
(SMOD)
0
1
Baudrate
Clock
Note: The switch configuration shows the reset state
MCS04074
Figure 6-41 Baudrate Generation for the Serial Port
Depending on the programmed operating mode different paths are selected for the
baudrate clock generation. Figure 6-41 shows the dependencies of the serial port
baudrate clock generation on the two control bits and from the mode which is selected
in the special function register SCON.
6.4.3.1 Baudrate in Mode 0
The baudrate in Mode 0 is fixed to:
Mode 0 baudrate = ^{oscillator frequency}
3
6.4.3.2 Baudrate in Mode 2
The baudrate 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 baudrate is 1/16 of the oscillator
frequency. If SMOD = 1, the baudrate is 1/8 of the oscillator frequency.
Mode 2 baudrate = ^{2 SMOD} × oscillator frequency
16
User’s Manual
6-107
2001-05