80C31X2 Datasheet, PDF (32/62 Pages) NXP Semiconductors – 80C51 8-bit microcontroller family 4K/8K/16K/32K ROM/OTP 128B/256B RAM low voltage 2.7 to 5.5 V, low power, high speed 30/33 MHz

Philips Semiconductors
80C51 8-bit microcontroller family
4K/8K/16K/32K ROM/OTP, low voltage (2.7 to 5.5 V),
low power, high speed (30/33 MHz)
Product data
P80C3xX2; P80C5xX2;
P87C5xX2
D0
D1
D2
D3
D4
D5
D6
D7
D8
START
BIT
DATA BYTE
ONLY IN STOP
MODE 2, 3 BIT
SET FE BIT IF STOP BIT IS 0 (FRAMING ERROR)
SM0 TO UART MODE CONTROL
SM0 / FE SM1
SM2
REN
TB8
RB8
TI
RI
SCON
(98H)
SMOD1 SMOD0
–
0 : SCON.7 = SM0
1 : SCON.7 = FE
POF
GF1
GF0
PD
Figure 19. UART Framing Error Detection
IDL
PCON
(87H)
SU01191
D0
D1
D2
D3
D4
D5
D6
D7
D8
SM0
SM1
SM2
REN
TB8
RB8
TI
1
1
1
0
1
1
X
RI
SCON
(98H)
RECEIVED ADDRESS D0 TO D7
PROGRAMMED ADDRESS
COMPARATOR
IN UART MODE 2 OR MODE 3 AND SM2 = 1:
INTERRUPT IF REN=1, RB8=1 AND “RECEIVED ADDRESS” = “PROGRAMMED ADDRESS”
– WHEN OWN ADDRESS RECEIVED, CLEAR SM2 TO RECEIVE DATA BYTES
– WHEN ALL DATA BYTES HAVE BEEN RECEIVED: SET SM2 TO WAIT FOR NEXT ADDRESS.
Figure 20. UART Multiprocessor Communication, Automatic Address Recognition
SU00045
2003 Jan 24
32