IC80C51
IC80C31
IC80C51/31 INTERNAL BUS
TB8
WRITE
TO
SBUF
S
Q
D
SBUF
TXD
CL
ZERO DETECTOR
PHASE 2 CLOCK
(1/2 fOSC
)
STOP BIT GEN SHIFT
TX CONTROL
START
DATA
MODE 2
TX CLOCK
SEND
16
TI
SMOD 1
SMOD 0
2
SERIAL
PORT
INTERRUPT
16
(SMOD IS PCON. 7)
SAMPLE
1-TO-0
LOAD
RI
RX
CLOCK
SBUF
SHIFT
1FFH
START
BIT
TRANSITION
DETECTOR
RX CONTROL
DETECTOR
INPUT SHIFT REG.
(9 BITS)
RXD
LOAD
SBUF
SHIFT
SBUF
READ
SBUF
IC80C51/31 INTERNAL BUS
TX
CLOCK
WRITE TO SBUF
SEND
S1P1
DATA
TRANSMIT
SHIFT
START
BIT
D0
D1
D2
D3
D4
D5
D6
D7
TB8
TXD
TI
STOP BIT
STOP BIT GEN
RX
CLOCK
16 RESET
START
BIT
RXD
D0
D1
D2
D3
D4
D5
D6
RB8
D7
STOP
BIT
BIT DETECTOR SAMPLE TIMES
RECEIVE
SHIFT
RI
Figure 13. Serial Port Mode 2
S3-24
Integrated Circuit Solution Inc.
MC001-0B
ICSI [ INTEGRATED CIRCUIT SOLUTION INC ]
