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Acrosser AR-B1320 User Manual

Page 15

background image

A

A

R

R

-

-

B

B

1

1

3

3

2

2

0

0

U

U

s

s

e

e

r

r

s

s

G

G

u

u

i

i

d

d

e

e

2-7

(9)

Divisor Latch (LS, MS)

Byte Data

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

Present Error Difference

Between Desired and Actual

50

2304

---

75

1536

---

110

1047

0.026

134.5

857

0.058

150

768

---

300

384

---

600

192

---

1200

96

---

1800

64

---

2000

58

0.69

2400

48

---

3600

32

---

4800

24

---

7200

16

---

9600

12

---

14400

8

---

19200

6

---

28800

4

---

38400

3

---

57600

2

---

115200

1

---

Table 2-4 Serial Port Divisor Latch

2.8 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

(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.