Rainbow Electronics AT89LP216 - Manual (Page 44)

44
3621A–MICRO–6/06
AT89LP216 [Preliminary]
Figure 17-2. Serial Port Mode 1
TX
CLOCK
WRITE TO SBUF
INTERNAL BUS
READ
SBUF
LOAD
SBUF
SBUF
SHIFT
INPUT SHIFT REG.
(9 BITS)
BIT
DETECTOR
1-TO-0
TRANSITION
DETECTOR
SERIAL
PORT
INTERRUPT
WRITE
TO
SBUF
÷2
SMOD1
= 0
SMOD1
= 1
TIMER 1
OVERFLOW
RXD
RX CLOCK
RX CLOCK
RX CONTROL
START
START DATA
SEND
SAMPLE
ч16
ч16
TX CONTROL
TI TI
ZERO DETECTOR
SBUF
TXD
INTERNAL BUS
“1”
D Q
CL
S
LOAD
SBUF
SHIFT
SHIFT
1FFH
RI
SEND
DATA
SHIFT
TXD
TI
D0 D1 D2 D3 D4 D5 D6 D7
D0 D1 D2 D3 D4 D5 D6 D7
STOP BIT
TRANSMIT
START BIT
÷16 RESET
START BIT STOP BIT
RX
CLOCK
BIT DETECTOR SAMPLE TIMES
SHIFT
RECEIVE
RXD
RI