80CL31 Datasheet, PDF (17/40 Pages) NXP Semiconductors – Low-voltage single-chip 8-bit microcontrollers

Philips Semiconductors
Low-voltage single-chip 8-bit microcontrollers
Product specification
80CL31/80CL51
80CL51 Internal Bus
TB8
Write
to
SBUF
DS Q
SBUF
TxD
CL
Phase 2 Clock
(1/2 f_OSC)
Zero Detector
Mode 2
SMOD = 1
÷2
SMOD = 0
(SMOD is
PCON.7)
÷ 16
Serial
Port
Interrupt
Sample
1-to-0
Transition
Detector
RxD
Stop Bit
Start ^Gen.
Shift
TX Control
TX Clock
T1
Data
Send
÷ 16
RX Clock R1
Start
RX Control
Load
SBUF
Shift
1FFH
Bit Detector
Load
SBUF
Input Shift Register
(9 Bits)
Shift
S0 BUFFER
Read
SBUF
TX
Clock
80CL51 Internal Bus
Write to SBUF
Data
Shift
TxD
TI
Send
T
r
S1P1
a
n
s
m
i
Start Bit
D0
D1
D2
D3
D4
D5
D6
D7
TB8
Stop Bit
t
Stop Bit Gen.
RX
Clock
÷ 16 Reset
R
e
RxD
c
Bit Detector
e
Sample Times
i
v
Shift
e
RI
Start
Bit
D0
D1
D2
D3
D4
D5
D6
D7
RB8
Stop Bit
Figure 9. Serial Port Mode 2
January 1995
17