C517A_99 Datasheet, PDF (138/218 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Components
C517A
Special Function Register S0CON (Address 98H)
Special Function Register S0BUF (Address 99H)
Reset Value : 00H
Reset Value : XXH
Bit No. MSB
LSB
9FH 9EH 9DH 9CH 9BH 9AH 99H 98H
98H SM0 SM1 SM20 REN0 TB80 RB80 TI0 RI0 S0CON
7
99H
6
5
4
3
2
1
Serial Interface 0 Buffer Register
0
S0BUF
Bit
SM0
SM1
SM20
REN0
TB80
RB80
TI0
RI0
Function
Serial port 0 mode selection bits
SM0 SM1 Selected operating mode
0
0
Serial mode 0 : Shift register, fixed baud rate (f_OSC/12)
0
1
Serial mode 1 : 8-bit UART, variable baud rate
1
0
Serial mode 2 : 9-bit UART, fixed baud rate (f_OSC/32 or f_OSC/64)
1
1
Serial mode 3 : 9-bit UART, variable baud rate
Enable serial port 0 multiprocessor communication in modes 2 and 3
In mode 2 or 3, if SM20 is set to 1 then RI0 will not be activated if the received 9th
data bit (RB80) is 0. In mode 1, if SM20 = 1 then RI0 will not be activated if a valid
stop bit was not received. In mode 0, SM20 should be 0.
Serial port 0 receiver enable
Enables serial reception. Set by software to enable serial reception. Cleared by
software to disable serial reception.
Serial port 0 transmitter bit 9
TB80 Is the 9th data bit that will be transmitted in modes 2 and 3. Set or cleared
by software as desired.
Serial port 0 receiver bit 9
In modes 2 and 3, RB80 is the 9th data bit that was received. In mode 1, if
SM2 = 0, RB80 is the stop bit that was received. In mode 0, RB80 is not used.
Serial port 0 transmitter interrupt flag
TI0 is set by hardware at the end of the 8th bit time in mode 0, or at the beginning
of the stop bit in the other modes, in any serial transmission. TI0 must be cleared
by software.
Serial port 0 receiver interrupt flag
RI0 is set by hardware at the end of the 8th bit time in mode 0, or halfway through
the stop bit time in the other modes, in any serial reception (exception see SM20).
RI0 must be cleared by software.
Semiconductor Group
6-72