DS1339 Просмотр технического описания (PDF) - Dallas Semiconductor -> Maxim Integrated

Номер в каталоге

Компоненты Описание

производитель

DS1339

I2C Serial Real-Time Clock

Dallas Semiconductor -> Maxim Integrated 

DS1339 I2C Serial Real-Time Clock

sets the register pointer on the DS1339, with the DS1339 acknowledging the transfer. The master may

then transmit zero or more bytes of data, with the DS1339 acknowledging each byte received. The

address pointer increments 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 DS1339 while the serial clock is input on SCL. START and STOP conditions

are recognized as the beginning and end of a serial transfer (Figure 8). The slave address byte is the first

byte received after the START condition is generated by the master. The slave address byte contains the

7-bit DS1339 address, which is 1101000, followed by the direction bit (R/W), which is 1 for a read. After

receiving and decoding the slave address byte the slave outputs an acknowledge on the SDA line. The

DS1339 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 address pointer is incremented after each byte is transferred.

The DS1339 must receive a “not acknowledge” to end a read.

Figure 7. Data Write—Slave Receiver Mode

<Slave Address>

<Word Address (n)>

<Data(n)>

<Data(n+1)>

<Data(n+X)>

S 1101000 0 A XXXXXXXX A XXXXXXXX A XXXXXXXX A ... XXXXXXXX A P

S - Start

A - Acknowledge (ACK)

P - Stop

Master to slave

Slave to master

DATA TRANSFERRED

(X+1 BYTES + ACKNOWLEDGE)

Figure 8. Data Read (from Current Pointer Location)—Slave Transmitter Mode

<Slave Address>

<Data(n)>

<Data(n+1)>

<Data(n+2)>

<Data(n+X)>

S 1101000 1 A XXXXXXXX A XXXXXXXX A XXXXXXXX A ... XXXXXXXX A P

S - Start

A - Acknowledge (ACK)

P - Stop

A - Not Acknowledge (NACK)

Master to slave

Slave to master

DATA TRANSFERRED

(X+1 BYTES + ACKNOWLEDGE)

NOTE: LAST DATA BYTE IS FOLLOWED BY A NACK

Figure 9. Data Read (Write Pointer, Then Read)—Slave Receive and Transmit

<Word Address (n)>

<Slave Address>

S 1101000 0 A XXXXXXXX A Sr 1101000 1 A

<Data(n)>

<Data(n+1)>

<Data(n+2)>

<Data(n+X)>

XXXXXXXX A XXXXXXXX A XXXXXXXX A ... XXXXXXXX A P

S - Start

Sr - Repeated Start

A - Acknowledge (ACK)

P - Stop

A - Not Acknowledge (NACK)

Master to slave

Slave to master

DATA TRANSFERRED

(X+1 BYTES + ACKNOWLEDGE)

NOTE: LAST DATA BYTE IS FOLLOWED BY A NACK

18 of 19

Share Link: