AS3649

Datasheet - Detailed Descr i p ti on

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register address to the AS3649. This sets the register pointer on the AS3649. The master may then transmit zero or more bytes of

data, with the AS3649 acknowledging each byte received. 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 transmitted on SDA by the AS3649 while the serial clock

is input on SCL. START and STOP conditions are recognized as the beginning and end of a serial transfer (Figure 29 and Figure 30).

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

bit AS3649 address, which is 0110000, followed by the direction bit (R/W), which, for a read, is 1.

slave address byte the device outputs an acknowledge on the SDA line. The AS3649 then begins to transmit data starting with the reg-

ister 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 AS3649 must receive a “not acknowledge” to end a read.

Figure 28. Data Write - Slave Receiver Mode

Figure 29. Data Read (from Current Pointer Location) - Slave Transmitter Mode

13.The address for writing to the AS3649 is 60h = 01100000b

14.The address for read mode from the AS3649 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)>