mg82fel308 Megawin Technology, mg82fel308 Datasheet - Page 58

• Manufacturer Part Number: mg82fel308
• Description: A Single-chip Microcontroller Based On A High Performance 1-t Architecture 80c51
• Manufacturer: Megawin Technology

13.2. Serial Port Mode 1
10 bits are transmitted through TXD, or received through RXD: a start bit (0), 8 data bits (LSB first), and a stop bit
(1). On receive, the stop bit goes into RB8 in SCON. The baud rate is determined by the Timer 1 or Timer 2
overflow rate. Figure 13-1 shows the data frame in Mode 1 and Figure 13-6 shows a simplified functional diag
of the serial port in Mode 1.
Transmission is initiated by any instruction that uses SBUF as a destination register. The “write to SBUF” signal
requests the UART engine to start the transmission. After receiving a transmission request, the UART engine
would start the transmission at the raising edge of TX Clock. The data in the SBUF would be serial output on the
TXD pin with the data frame as shown in Figure 13-1 and data width depend on TX Clock. After the end of 8th
data transmission, TI would be asserted by hardware to indicate the end of data transmission.
Reception is initiated when Serial Port Controller detected 1-to-0 transition at RXD sampled by RCK. The data on
the RXD pin would be sampled by Bit Detector in Serial Port Controller. After the end of STOP-bit reception, RI
would be asserted by hardware to indicate the end of data reception and load STOP-bit into RB8 in SCON
register.
Figure 13-6 Serial Port Mode 1, 2, 3
This document information is the intellectual property of Megawin Technology.
© Megawin Technology Co., Ltd. 2009 All rights reserved.
QP-7300-03D
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Mode 2
clock source
♦
SYSCLK/2
“ 0＂
2
“ 1＂
MEGAWIN
MAKE YOU WIN
Overflow
Timer 2
“ 1＂
“ 1＂
Mode 1, 3
clock source
♦
2
“ 0＂
“ 0＂
“ 0＂
Overflow
Timer 1
“ 1＂
SM1
RCLK
SM1
SMOD1
TCLK
1
1
0
0
RCK
♦
♦
16
16
SM0
SM1
TB8
SMOD2
TX Clock
RX Clock
SBUF
SBUF
Write
Read
80C51 Internal BUS
80C51 Internal BUS
UART engine
MG82FE(L)308/316
TI
RI
STOP -Bit
9th-Bit
RXBUF
TXBUF
SM0
0
1
Preliminary, v 0.04
TxD
RxD
Serial Port
Interrupt
RB8
ram