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AS3642

Datasheet - D e ta i l e d D e s c r i p t i o n

The address pointer will increment after each data byte is transferred. The master generates a STOP condition

to terminate the data write.

2. Slave Transmitter Mode (Read Mode): The first byte is received and handled as in the slave receiver mode.

However, in this mode, the direction bit indicates that the transfer direction is reversed. Serial data is transmit-

ted on SDA by the AS3642 while the serial clock is input on SCL. START and STOP conditions are recognized

as the beginning and end of a serial transfer (Figure 22 and Figure 23). The slave address byte is the first byte

received after the master generates a START condition. The slave address byte contains the 7-bit AS3642

address, which is 0110000, followed by the direction bit (R/W), which, for a read, is 1.

decoding the slave address byte the device outputs an acknowledge on the SDA line. The AS3642 then

begins to transmit data starting with the register address pointed to by the register pointer. If the register

pointer is not written to before the initiation of a read mode the first address that is read is the last one stored in

the register pointer. The AS3642 must receive a “not acknowledge” to end a read.

Figure 21. Data Write - Slave Receiver Mode

Figure 22. Data Read (from Current Pointer Location) - Slave Transmitter Mode

6. The address for read mode from the AS3642 is 61h = 01100001b

S

0110000

0

A

XXXXXXXX

A

AA

XXXXXXXX

XXXXXXXX

A

XXXXXXXX

P

<Slave Address>

<Word Address (n)>

<Data(n)>

<Data(n+1)>

<Data(n+X)>

S - Start

A - Acknowledge (ACK)

P - Stop

Data Transferred

(X + 1 Bytes + Acknowledge)

S

0110000

1

A

XXXXXXXX

A

AA

XXXXXXXX

XXXXXXXX

NA

XXXXXXXX

P

<Slave Address>

<Data(n)>

<Data(n+1)>

<Data(n+X)>

S - Start

A - Acknowledge (ACK)

P - Stop

NA - Not Acknowledge (NACK)

Data Transferred

(X + 1 Bytes + Acknowledge)

Note: Last data byte is followed by a NACK

<Data(n+2)>