TOIM4232

Document Number 82546

Rev. 1.5, 06-Jun-06

Vishay Semiconductors

www.vishay.com

5

Baud Rate Select Words

Note: IrDA standard only supports 2.4, 9.6, 19.2, 57.6, and 115.2 kbit/s.

Software for the TOIM4232

UART Programming

For proper operation, the RS232 must be programmed (using 8 bit, 1 stop, no parity) to send a two character control word, YZ. The control

word YZ is composed of two characters, written in hexadecimal, in format: YZ. The transfer rate for programming must be identical with

the formerly programmed data rate, or after resetting the TOIM4232, the default rate of 9600 bit/s is used.

*) For programming the UART, refer to e.g., National Semiconductor’s data sheet of PC 16550 UART

B3

B2

B1

B0

Char

Baud Rate

00

00

0

115.2 k

00

11

57.6 k

01

02

38.4 k

01

13

19.2 k

10

04

14.4 k

10

15

12.8 k

11

06

9.6 k

11

17

7.2 k

10

00

8

4.8 k

00

19

3.6 k

01

0

A

2.4 k

01

1

B

1.8 k

10

0

C

1.2 k

10

1

D

forbidden

11

0

E

forbidden

11

1

F

forbidden

Step.

RESET

BR/ D

TD_UART

RD_UART

RD_IR

TD_IR

Description and Comments

1

High

XXXX

X

Resets all internal registers. Resets to

IrDA default data rate of 9600 bit/s

2

Low

XXXX

X

Wait at least 2 ms, to allow start-up of

internal clock. When external clock is

used: Wait at least 7 µs.

3

Low

High

X

X

X

X

Wait at least 7 µs. TOIM4232 now is set

to the Control Word programming mode

4Low

High

YZ

with Y = 1

for 1.627 µs

Y = 0

3/16 bit

length

X

X

X

Sending the Control Word YZ.

Examples: Send "1Z" if 1.627 µs pulses

are intended to be used. Otherwise

send "0Z" for 3/16 bit period pulses.

"Y6" keeps the 9.6 kbit/s data rate.

Z = 0 sets to 115.2 kbit/s, see

programming table.

Wait at least 1 µs for hold-time.

5

Low

Low

DATA

DATA

DATA

DATA

With BR/D = 0, TOIM4232 is in the data

communication mode. Both RESET

and BR/D must be kept LOW ("0")

during data transmission.

Reprogramming to a new data rate can

be resumed by restarting from step 3.

The UART itself also must set to the

correct data rate *).