Acrosser AR-B1550 - Manual (Page 14)

AR-B1550 User s Guide
12
Desired Baud Rate Divisor Used to Generate 16x Clock
300 384
600 192
1200 96
1800 64
2400 48
3600 32
4800 24
9600 12
14400 8
19200 6
28800 4
38400 3
57600 2
115200 1
Serial Port Divisor Latch
2.6 PARALLEL PORT
(1) Register Address
Port Address Read/Write Register
base + 0 Write Output data
base + 0 Read Input data
base + 1 Read Printer status buffer
base + 2 Write Printer control latch
Registers’ Address
(2) Printer Interface Logic
The parallel port of the W83977F-A is for attaching various devices that accept eight bits of parallel data at
standard TTL level.
(3) Data Swapper
The system microprocessor can read the contents of the printer’s Data Latch through the Data Swapper by reading
the Data Swapper address.
(4) Printer Status Buffer
The system microprocessor can read the printer status by reading the address of the Printer Status Buffer. The bit
definitions are described as follows:
X X X
1 2 3 4 5 6 7 0
-ERROR
SLCT
PE
-ACK
-BUSY
Printer Status Buffer
NOTE: X presents not used.