T89C51CC02 Atmel, T89C51CC02 Datasheet - Page 45

• Manufacturer Part Number: T89C51CC02
• Description: 8-Bit MCU
• Manufacturer: Atmel

11. Serial I/O Port
The T89C51CC02 I/O serial port is compatible with the I/O serial port in the 80C52.
It provides both synchronous and asynchronous communication modes. It operates as a Universal Asynchronous
Receiver and Transmitter (UART) in three full-duplex modes (Modes 1, 2 and 3). Asynchronous transmission and
reception can occur simultaneously and at different baud rates
Serial I/O port includes the following enhancements:
11.1. Framing Error Detection
Framing bit error detection is provided for the three asynchronous modes. To enable the framing bit error detection
feature, set SMOD0 bit in PCON register.
When this feature is enabled, the receiver checks each incoming data frame for a valid stop bit. An invalid stop
bit may result from noise on the serial lines or from simultaneous transmission by two CPUs. If a valid stop bit
is not found, the Framing Error bit (FE) in SCON register bit is set.
Rev.A - May 17, 2001
Framing error detection
Automatic address recognition
TXD
RXD
SM0/FE
SMOD1
SMOD0
SM1
Transmitter
Figure 25. Serial I/O Port Block Diagram
SBUF
Figure 26. Framing Error Block Diagram
SM2
-
REN
Set FE bit if stop bit is 0 (framing error)
SM0 to UART mode control
To UART framing error control
POF
Mode 0 Transmit
Preliminary
IB Bus
Write SBUF
SCON
RI
TB8
GF1
TI
RB8
GF0
Shift register
PD
TI
Receive
Receiver
SBUF
IDL
RI
Read SBUF
Load SBUF
T89C51CC02
Interrupt Request
Serial Port
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