P89V51RD2 Philips Semiconductors, P89V51RD2 Datasheet - Page 35

• Manufacturer Part Number: P89V51RD2
• Description: 8-bit 80C51 5 V low power 64 kB Flash microcontroller with 1 kB RAM
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 12964
Product data
7.5.1 Mode 0
7.5.2 Mode 1
7.5.3 Mode 2
7.5.4 Mode 3
7.5 UARTs
Table 22:
The UART operates in all standard modes. Enhancements over the standard 80C51
UART include Framing Error detection, and automatic address recognition.
Serial data enters and exits through RxD and TxD outputs the shift clock. Only 8 bits
are transmitted or received, LSB first. The baud rate is fixed at
frequency. UART configured to operate in this mode outputs serial clock on TxD line
no matter whether it sends or receives data on RxD line.
10 bits are transmitted (through TxD) or received (through RxD): a start bit (logical 0),
8 data bits (LSB first), and a stop bit (logical 1). When data is received, the stop bit is
stored in RB8 in Special Function Register SCON. The baud rate is variable and is
determined by the Timer
11 bits are transmitted (through TxD) or received (through RxD): start bit (logical 0), 8
data bits (LSB first), a programmable 9th data bit, and a stop bit (logical 1). When
data is transmitted, the 9th data bit (TB8 in SCON) can be assigned the value of 0 or
(e.g. the parity bit (P, in the PSW) could be moved into TB8). When data is received,
the 9th data bit goes into RB8 in Special Function Register SCON, while the stop bit
is ignored. The baud rate is programmable to either
frequency, as determined by the SMOD1 bit in PCON.
11 bits are transmitted (through TxD) or received (through RxD): a start bit (logical 0),
8 data bits (LSB first), a programmable 9th data bit, and a stop bit (logical 1). In fact,
Mode 3 is the same as Mode 2 in all respects except baud rate. The baud rate in
Mode 3 is variable and is determined by the Timer
Table 23:
Bit addressable; Reset value: 00H
Baud rate
220
600
220
Bit
Symbol SM0/FE
Timer 2 generated commonly used baud rates
SCON - Serial port control register (address 98H) bit allocation
7
Rev. 01 — 01 March 2004
SM1
Osc freq
12 MHz
6 MHz
6 MHz
6
1
2
overflow rate.
SM2
5
REN
4
Timer 2
RCAP2H
F2
FD
F9
8-bit microcontrollers with 80C51 core
TB8
1
3
1
2
16
overflow rate.
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
…continued
or
RB8
1
P89V51RD2
32
2
of the CPU clock
1
RCAP2L
AF
8F
57
6
of the CPU clock
TI
1
RI
35 of 75
0