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6 parallel port – Acrosser AR-B9622 User Manual

Page 15

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AR-B9622 User¡¦

s Guide

2-7

(9) Divisor Latch (LS, MS)

LS

MS

Bit 0:

Bit 0

Bit 8

Bit 1:

Bit 1

Bit 9

Bit 2:

Bit 2

Bit 10

Bit 3:

Bit 3

Bit 11

Bit 4:

Bit 4

Bit 12

Bit 5:

Bit 5

Bit 13

Bit 6:

Bit 6

Bit 14

Bit 7:

Bit 7

Bit 15

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

Table 2-5 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

Table 2-6 Registers’ Address

(2) Printer Interface Logic

The parallel portion of the SMC37C669 makes the attachment of 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.