SBAS883A February 2018 – June 2018 OPT3101
PRODUCTION DATA.
The I2C host of the OPT3101 device automatically loads all of the registers (256 bytes) from an external 2KB (256 × 8) EEPROM on device reset to configure the device. Of these 256 bytes, 64 bytes are register address, and 192 bytes are data bytes. So from EEPROM, the device can auto load any of up to 64 device registers of 24 bits each (64 × 24). EEPROM data should be written in the following format. If only part of the memory is used, the rest of the memory should be filled with all 0x00 or 0xFF.
ADDRESS | DATA [7:0] |
---|---|
0 | Register address i |
1 | Register data i[7:0] |
2 | Register data i[15:8] |
3 | Register data i[23:16] |
4 | Register address j |
5 | Register data j[7:0] |
6 | Register data j[15:8] |
7 | Register data j[23:16] |
… | … |
255 | Register data k[23:16] |
The EEPROM I2C slave address should be 0x50h. On device reset, I2C host initiates auto load from the external EEPROM connected on the SDA_M, SCL_M bus. If there is an EEPROM device on the bus, this load operation performs the 256-byte read operation. If there is no EEPROM on the host bus, the device terminates auto load after the first transaction. During I2C host auto load, if an external host writes to the OPT3101 I2C slave, it acknowledges but data transfer does not happen (write/read). Register address 0 of the OPT3101 device cannot be loaded from the OPT3101 I2C host. Register address 0 is always reserved for I2C slave. By writing to register bit 0[22] (FORCE_EN_SLAVE) of the OPT3101 device, I2C slave can take control of register access from host auto load. If there are no pullup resistors connected on the I2C host bus SDA_M and SCL_M, then register bit 0[22] (FORCE_EN_SLAVE) = 1 should be written before any other I2C register writes, otherwise the device register read/write does not happen. If the device is to be used in monoshot mode, I2C host power down disable should be written first (DIS_GLB_PD_I2CHOST) before writing monoshot mode enable (MONOSHOT_MODE) bit in the EEPROM.