W79E825A Datasheet, PDF (26/127 Pages) Winbond – 8-BIT MICROCONTROLLER

W79E825A/824A/823B/822B Data Sheet
MODE
0
1
2
3
SM0
0
0
1
1
SM1
0
1
0
1
SM0, SM1: Mode Select bits
DESCRIPTION
LENGTH
BAUD RATE
Synchronous
8
Tclk divided by 4 or 12
Asynchronous
10
Variable
Asynchronous
11
Tclk divided by 32 or 64
Asynchronous
11
Variable
SERIAL DATA BUFFER
Bit: 7
SBUF.7
6
SBUF.6
5
SBUF.5
4
SBUF.4
3
SBUF.3
2
SBUF.2
1
SBUF.1
0
SBUF.0
Mnemonic: SBUF
Address: 99h
BIT NAME
FUNCTION
Serial data on the serial port is read from or written to this location. It actually
7-0
SBUF.[7:0]
consists of two separate internal 8-bit registers. One is the receive resister, and
the other is the transmit buffer. Any read access gets data from the receive data
buffer, while write access is to the transmit data buffer.
PORT 2
Bit: 7
6
5
4
3
2
1
0
-
-
-
-
-
-
P2.1
P2.0
Mnemonic: P2
Address: A0h
BIT NAME
FUNCTION
7-2
-
Reserved
1
P2.1 XTAL1 clock input pin.
0
P2.0 XTAL2 or CLKOUT pin by alternative.
Note: The initial value of the port is set by CONFIG1.PRHI bit. The default setting for CONFIG1.PRHI =1 which the alternative
function output is turned on upon reset. If CONFIG1.PRHI is set to 0, the user has to write a 1 to port SFR to turn on the
alternative function output.
KEYBOARD INTERRUPT
Bit: 7
KBI.7
6
KBI.6
5
KBI.5
4
KBI.4
3
KBI.3
2
KBI.2
1
KBI.1
0
KBI.0
Mnemonic: KBI
Address: A1h
BIT NAME
FUNCTION
7
KBI.7 1: Enable P0.7 as a cause of a Keyboard interrupt.
6
KBI.6 1: Enable P0.6 as a cause of a Keyboard interrupt.
5
KBI.5 1: Enable P0.5 as a cause of a Keyboard interrupt.
4
KBI.4 1: Enable P0.4 as a cause of a Keyboard interrupt.
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