Advertisement
MSM80C154S/83C154S
Serial port control register (SCON)
NAME
ADDRESS
SCON
98H
BIT LOCATION
FLAG
SCON.0
RI
SCON.1
TI
SCON.2
RB8
SCON.3
TB8
SCON.4
REN
SCON.5
SM2
SCON.6
SM1
SCON.7
SM0
272
MSB
7
6
5
SM0
SM1
SM2
"End of serial port reception" interrupt request flag.
This flag must be reset by software during interrupt service routine.
This flag is set after the eighth bit of data has been received when in mode 0, or
by the STOP bit when in any other mode.
In mode 2 or 3, however, RI is not set if the RB8 data is "0" with SM2 = "1".
RI is set in mode 1 if STOP bit is received when SM2 = "1".
"End of serial port tramsmission" interrupt request flag. This flag must be reset
by software during interrupt service routine.
This flag is set after the eighth bit of data has been sent when in mode 0, or after
the last bit of data has been sent when in any other mode.
The ninth bit of data received in mode 2 or 3 is passed to RB8.
The STOP bit is applied to RB8 if SM2 = "0" when in mode 1.
RB8 can not be used in mode 0.
The TB8 data is sent as the ninth data bit when in mode 2 or 3.
Any desired data can be set in TB8 by software.
Reception enable control bit.
No reception when REN = "0".
Reception enabled when REN = "1".
If the ninth bit of received data is "0" with SM2 = "1" in mode 2 or 3, the "end of
reception" signal is not set in the RI flag.
The "end of reception" signal set in the RI flag if the STOP bit is not "1" when
SM2 = "1" in mode 1.
SM0
SM1
MODE
0
0
0
0
1
1
1
0
2
1
1
3
¡ Semiconductor
4
3
2
REN
TB8
RB8
FUNCTION
8-bit shift register I/O
8-bit UART variable baud rate
9-bit UART 1/32 XTAL1, 1/64 XTAL1 baud rate
9-bit UART variable baud rate
LSB
1
0
TI
RI
Advertisement
