IC80C51
IC80C31
IC80C51/31 INTERNAL BUS
WRITE
TO
SBUF
RXD
S
Q
D
P3.0 ALT
OUTPUT
FUNCTION
SBUF
CL
SHIFT
ZERO DETECTOR
TX CONTROL
START
SHIFT
SEND
S6
TX CLOCK
TXD
SERIAL
PORT
INTERRUPT
P3.1 ALT
OUTPUT
FUNCTION
SHIFT
CLOCK
RI
RX CLOCK
START
RECEIVE
SHIFT
RX CONTROL
REN
RI
1
1 1 1 1 1 1 0
RXD
P3.0 ALT
INPUT
INPUT SHIFT REG.
FUNCTION
LOAD
SBUF
SHIFT
SBUF
READ
SBUF
IC80C51/31 INTERNAL BUS
S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6 S1
ALE
WRITE TO SBUF
SEND
S6P2
SHIFT
D0
D1
D2
D3
D5
D6
D7
D4
RXD (DOUT
)
TRANSMIT
TXD (SHIFT CLOCK)
TI
S3P1
S6P1
WRITE TO SCON (CLEAR RI)
RI
RECEIVE
SHIFT
RECEIVE
RXD (DIN
)
D3
D5
D6
D7
D4
D1
D2
D0
S5P2
TXD (SHIFT CLOCK)
Figure 11. Serial Port Mode 0
S3-22
Integrated Circuit Solution Inc.
MC001-0B
ICSI [ INTEGRATED CIRCUIT SOLUTION INC ]
