Write commands, At83c24 – Rainbow Electronics AT83C24NDS User Manual

Page 8

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4234F–SCR–10/05

AT83C24

Write Commands

The write commands are:

1.

Reset:

Initializes all the logic and the TWI interface as after a power-up or power-fail reset. If a
smart card is active when RESET falls, a deactivation sequence is performed. This is a one-
byte command.

2.

Write Config:

Configures the device according to the last six bits in the CONFIG0 register and to the fol-
lowing four bytes in CONFIG1, CONFIG2, CONFIG3 then CONFIG4 registers. This is a
five bytes command.

Figure 3. Command byte format for Write CONFIG0 command

3.

Write Timer:

Program the 16-bit automatic reset transition timer with the following two bytes. This is a
three bytes command.

4.

Write Interface:

Program the interface. This is a one-byte command. The MSB of the command byte is fixed
at 0.

5.

General Call Reset:

A general call followed by the value 06h has the same effect as a Reset command.

Table 3. Write Commands Description

Address Byte

(See Table 2)

Command Byte

Data Byte
1

Data Byte
2

Data Byte
3

Data Byte
4

1. Reset

0100 A

2

A

1

A

0

0

1111 1111

2. Write config

0100 A

2

A

1

A

0

0

(10 + CONFIG0 6
bits)

CONFIG1

CONFIG2

CONFIG3

CONFIG4

3. Write Timer

0100 A

2

A

1

A

0

0

1111 1100

TIMER1

TIMER0

4. Write Interface

0100 A

2

A

1

A

0

0

(0+INTERFACE 7
bits)

5. General Call
Reset

0000 0000

0000 0110

b7

b6

b5

b4

b3

b2

b1

1

X

0

X

X

X

X

CONFIG0 on 6 Bits

b0

X

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