Ver.1.02

COM-2(FIT)GY

4

The output baud rate can be set by setting the appropriate

value to the Baud Rate Generator resister.

The available

setting range depends on which clock mode is used.

Clock 3 mode: 15 - 921,600bps

Clock 2 mode: 8 - 460,800bps

Clock 1 mode: 4 - 230,400bps

Clock 0 mode: 2 - 115,200bps

However, some baud rate values do not have a corresponding

Baud Rate Generator resister setting.

If the result of

substituting the baud rate into the equation below is an integer,

then that baud rate can be set.

If the result contains a

fractional part, the baud rate cannot be set.

Clock 3 mode

921600 ÷ Desired baud rate

= Division resister setting value

Ex.) 921600 ÷ 9600bps

= 96 (As the result is an integer, this

baud rate can be set.)

921600 ÷ 128000bps

= 7.2 (As the result contains a

fractional part, this baud rate cannot be set.)

Clock 2 mode

460800 ÷ Desired baud rate

= Division resister setting value

Ex.) 460800 ÷ 9600bps

= 48 (As the result is an integer, this

baud rate can be set.)

460800 ÷ 128000bps

= 3.6 (As the result contains a

fractional part, this baud rate cannot be set.)

Clock 1 mode

230400 ÷ Desired baud rate

= Division resister setting value

Ex.) 230400 ÷ 9600bps

= 24 (As the result is an integer, this

baud rate can be set.)

230400 ÷ 128000bps

= 1.8 (As the result contains a

fractional part, this baud rate cannot be set.)

Clock 0 mode

115200 ÷ Desired baud rate

= Division resister setting value

Ex.) 115200 ÷ 9600bps

= 12 (As the result is an integer, this

baud rate can be set.)

115200 ÷ 76800bps

= 1.5 (As the result contains a

fractional part, this baud rate cannot be set.)

CAUTION

See the manual Chapter 5 “Interrupt Vector Resisters” for

selecting the clock frequency (1.8432, 3.6864, 7.3728, or

14.7456 MHz).

For use in compatible mode, clock 0 (1.8432 MHz) is used as

a fixed setting.

Refer to the following baud rate setting examples.

Baud rates

other than those listed below can also be set if they produce a

valid setting value in the equation described above.

Baud Rate Generator Programming Table

Clock 0 mode

(1.8432MHz)

Clock 1 mode

(3.6864MHz)

Clock 2 mode

(7.3728MHz)

Clock 3 mode

(14.7456MHz)

Output

baud rate

Baud Rate

Generator

resister

Setup

error

(%)

Baud Rate

Generator

resister

Setup

error

(%)

Baud Rate

Generator

resister

Setup

error

(%)

Baud Rate

Generator

resister

Setup

error

(%)

2

57600

-

4

28800

-

57600

-

5

23040

-

46080

-

8

14400

-

28800

-

57600

-

15

7680

-

15360

-

30720

-

61440

-

50

2304

-

4608

-

9216

-

18432

-

75

1536

-

3072

-

6144

-

12288

-

110

1047

0.026

2094

0.026

4189

0.0022

8378

0.0022

134.5

857

0.058

1713

0.0006

3426

0.0006

6852

0.0006

150

768

-

1536

-

3072

-

6144

-

300

384

-

768

-

1536

-

3072

-

600

192

-

384

-

768

-

1536

-

1200

96

-

192

-

384

-

768

-

1800

64

-

128

-

256

-

512

-

2000

58

0.68

115

0.17

230

0.17

461

0.04

2400

48

-

96

-

192

-

384

-

3600

32

-

64

-

128

-

256

-

4800

24

-

48

-

96

-

192

-

7200

16

-

32

-

64

-

128

-

9600

12

-

24

-

48

-

96

-

14400

8

-

16

-

32

-

64

-

19200

6

-

12

-

24

-

48

-

28800

4

-

8

-

16

-

32

-

38400

3

-

6

-

12

-

24

-

57600

2

-

4

-

8

-

16

-

76800

3

-

6

-

12

-

115200

1

-

2

-

4

-

8

-

153600

3

-

6

-

230400

1

-

2

-

4

-

460800

1

-

2

-

921600

1

-

TxD, RTS, DTR

RxD, CTS, DSR, DCD, RI

MAX3245

Stack Connector

Control Circuit

UART

XR16C2850

Compatible

Driver

Receiver

Driver

Receiver

Device ID

Interface Connector CH0

Interface Connector CH1

Setting the Baud Rate

Equivalence Circuit

Block Diagram