SLDS231 August 2018 PGA305
PRODUCTION DATA.
Figure 18 shows the basic protocol of the I2C frame for a Write operation.
The diagram represents the data fed into or out from the I2C SDA port.
The basic data transfer is to send two bytes of data to the specified slave address. The first data field is the register address and the second data field is the data sent or received.
The I2C slave address is used to determine which memory page is being referenced. Table 5 shows the mapping of the slave address to the memory page.
SLAVE ADDRESS WHEN I2CADDR = 1 | SLAVE ADDRESS WHEN I2CADDR = 0 | PGA305 MEMORY PAGE |
---|---|---|
0x20 | 0x40 | PGA305 Data Read and COMPENSATION_CONTROL register (di_page_address = 0x00) |
0x22 | 0x42 | Control and Status Registers (di_page_address = 0x02) |
0x25 | 0x45 | EEPROM Registers (di_page_address = 0x05) |
Figure 19 shows the basic PGA305 I2C protocol for a read operation.
The slave address determines the memory page. The R/W bit is set to 0.
The register address specifies the 8-bit address of the requested data.
The repeat start condition replaces the write data from the above write operation description. This informs the PGA305 devices that Read operation will take place instead of a write operation.
The second slave address contains the memory page from which the data will be retrieved. The R/W bit is set to 1.
Slave data is transmitted after the acknowledge is received by the master.
Table 6 lists a few examples of I2C Transfers.
COMMAND | MASTER TO SLAVE DATA ON I2C SDA
(I2CADDR = 0) |
MASTER TO SLAVE DATA ON I2C SDA
(I2CADDR = 1) |
---|---|---|
Write 0x80 to Control and Status Registers 0x30 (DAC_REG0_1) |
Slave address: 010 0010 Register address: 0011 0000 Data: 1000 0000 |
Slave address: 100 0010 Register address: 0011 0000 Data: 1000 0000 |
Read from EEPROM Byte 7 |
Slave Address: 010 0101 Register Address: 0000 0111 |
Slave Address: 100 0101 Register Address: 0000 0111 |
Write to EEPROM Cache Byte 7 |
Slave Address: 010 0101 Register Address: 1000 0111 |
Slave Address: 100 0101 Register Address: 1000 0111 |