C505_9708 SIEMENS [Siemens Semiconductor Group], C505_9708 Datasheet - Page 107

• Manufacturer Part Number: C505_9708
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Special Function Register SCON (Address 98 H )
Special Function Register SBUF (Address 99 H )
Bit
SM0
SM1
SM2
REN
TB8
RB8
TI
RI
Semiconductor Group
Bit No.
99 H
98 H
MSB
SM0
Function
Serial port 0 operating mode selection bits
Enable serial port multiprocessor communication in modes 2 and 3
In mode 2 or 3, if SM2 is set to 1 then RI will not be activated if the received 9th
data bit (RB8) is 0. In mode 1, if SM2 = 1 then RI will not be activated if a valid
stop bit was not received. In mode 0, SM2 should be 0.
Enable receiver of serial port
Enables serial reception. Set by software to enable serial reception. Cleared by
software to disable serial reception.
Serial port transmitter bit 9
TB8 is the 9th data bit that will be transmitted in modes 2 and 3. Set or cleared by
software as desired.
Serial port receiver bit 9
In modes 2 and 3, RB8 is the 9th data bit that was received. In mode 1, if SM2 = 0,
RB8 is the stop bit that was received. In mode 0, RB8 is not used.
Serial port transmitter interrupt flag
TI 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. TI must be cleared
by software.
Serial port receiver interrupt flag
RI 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 SM2).
RI must be cleared by software.
7
9F H
SM0
0
0
1
1
SM1
9E H
6
SM1
0
1
0
1
Serial Interface Buffer Register
SM2
9D H
5
Selected operating mode
Serial mode 0 : Shift register, fixed baud rate (
Serial mode 1 : 8-bit UART, variable baud rate
Serial mode 2 : 9-bit UART, fixed baud rate (
Serial mode 3 : 9-bit UART, variable baud rate
REN
9C H
4
6-45
9B H
TB8
3
On-Chip Peripheral Components
RB8
9A H
2
99 H
1
TI
LSB
98 H
0
RI
Reset Value : XX H
f
Reset Value : 00 H
OSC
C505 / C505C
f
OSC
/16 or
SBUF
SCON
/6)
1997-08-01
f
OSC
/32)