C8051T630DK Silicon Laboratories Inc, C8051T630DK Datasheet - Page 148

• Manufacturer Part Number: C8051T630DK
• Description: KIT DEV FOR C8051T630 FAMILY
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051T630DK

• Contents: Board, daughter boards, power adapter, cables, documentation and software
• Processor To Be Evaluated: C8051T63x
• Interface Type: USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: C8051T630, T631, T632, T633, T634 and T635 MCUs
• For Use With: 336-1465 - BOARD SOCKET DAUGHTER 20-QFN
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1464

C8051T630/1/2/3/4/5
22. UART0
UART0 is an asynchronous, full duplex serial port offering modes 1 and 3 of the standard 8051 UART.
Enhanced baud rate support allows a wide range of clock sources to generate standard baud rates (details
in Section “22.1. Enhanced Baud Rate Generation” on page 149). Received data buffering allows UART0
to start reception of a second incoming data byte before software has finished reading the previous data
byte.
UART0 has two associated SFRs: Serial Control Register 0 (SCON0) and Serial Data Buffer 0 (SBUF0).
The single SBUF0 location provides access to both transmit and receive registers. Writes to SBUF0
always access the Transmit register. Reads of SBUF0 always access the buffered Receive register;
it is not possible to read data from the Transmit register.
With UART0 interrupts enabled, an interrupt is generated each time a transmit is completed (TI0 is set in
SCON0), or a data byte has been received (RI0 is set in SCON0). The UART0 interrupt flags are not
cleared by hardware when the CPU vectors to the interrupt service routine. They must be cleared manually
by software, allowing software to determine the cause of the UART0 interrupt (transmit complete or receive
complete).
148
Rate Generator
UART Baud
Write to
SBUF
Figure 22.1. UART0 Block Diagram
Tx Clock
Rx Clock
Stop Bit
Start
Start
SBUF
Read
SCON
D
TB8
SET
CLR
Shift
Q
Input Shift Register
Shift
SFR Bus
(RX Latch)
Rx Control
(9 bits)
Tx Control
SBUF
0x1FF
SFR Bus
Zero Detector
(TX Shift)
Rev. 1.0
SBUF
RB8
Load SBUF
Tx IRQ
Rx IRQ
TI
RI
SBUF
Load
Data
Send
Interrupt
Serial
Port
TX
RX
Crossbar
Crossbar
Port I/O