Megawin Technology Co., Ltd.
MG87FE/L52
Mode2
11 bits are transmitted through TXD or received through RXD. The frame data includes a start
bit(0), 8 data bits, a programmable 9th bit and a stop bit(1). On transmit, the 9th data bit comes
from TB8 in SCON. On receive, the 9th data bit goes into RB8 in SCON. The baud rate is
programmable to either 1/32 or 1/64 the frequency of system clock (CLKin).
Mode3
Mode 3 is the same as mode 2 except the baud rate is variable.
In all four modes, transmission is initiated by any instruction that use SBUF as a destination
register. Reception is initiated in mode 0 by the condition RI = 0 and REN = 1. Reception is
initiated in the other modes by the incoming start bit with 1-to-0 transition if REN = 1.
Automatic Address Recognition
Automatic Address Recognition is a feature which allows the UART to recognize certain
addresses in the serial bit stream by using hardware comparison circuit. This feature improves
the overhead of software by eliminating the need in examine every incoming address. This
feature is enabled by setting the SM2 bit in SCON. In mode2 and mode3, the receive interrupt
flag(RI) will be automatically set when the received byte contains either the “Given” address or
the “Broadcast” address. These two modes require the 9th received bit is a 1 to indicate that
received information is an address and not the data byte.
In mode1, the RI flag will be set if SM2 is enabled and a valid stop bit is received which the stop
bit follows the 8 address bits and the information is either a Given or Broadcast address.
In mode 0, SM2 is ignored.
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Preliminary ver 1.3
Date: 2009-JAN-20
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
