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MSM80C154S/83C154S/85C154HVS
70
4.4.2.4 Serial port control register (SCON)
SCON 98H SM0 SM1 SM2 REN TB8 RB8 TI RI
Name Address
MSB LSB
76543210
Bit location Flag Function
SCON.0
SCON.1
SCON.2
SCON.3
SCON.4
SCON.5
SCON.6
SCON.7
RI
TI
RB8
TB8
REN
SM2
SM1
SM0
"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 if STOP bit is received when SM2="1" in mode 1.
"End of serial port transmission" 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 R88 if SM2="0" when in mode 1. RB8
cannot 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.
Nor is the "end of reception" signal set in the RI flag if the STOP bit
is not "1" when SM2="1" in mode 1.
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
MODESM1SM0
000
011
102
113