The DS320PR410 can also be configured by reading from EEPROM. To enter into this mode, the MODE pin must be set to L1. The EEPROM load operation only happens once after the device's initial power-up. If the DS320PR410 is configured for SMBus Primary mode, then it will remain in the SMBus IDLE state until the READ_EN_N pin is asserted to LOW. After the READ_EN_N pin is driven LOW, the DS320PR410 becomes an SMBus primary and attempts to self-configure by reading the device settings stored in an external EEPROM (SMBus 8-bit address 0xA0). When the DS320PR410 has finished reading from the EEPROM successfully, it will drive the DONEn pin LOW. SMBus/I²C secondary operation is available in this mode before, during, or after EEPROM reading. Note: during EEPROM reading, if the external SMBus/I²C primary wants to access DS320PR410 registers, then it must support arbitration.

When designing a system for using the external EEPROM, the user must follow these specific guidelines:

• EEPROM size of 2 Kb (256 × 8-bit) is recommended.
• Set MODE = L1, configure for SMBus Primary mode.
• The external EEPROM device address byte must be 0xA0 and capable of 400 kHz operation at 3.3 V supply
• In SMBus/I²C modes the SCL and SDA pins must be pulled up to a 3.3 V supply with a pull-up resistor. The value of the resistor depends on total bus capacitance. 4.7 kΩ is a good first approximation for a bus capacitance of 10 pF.

Figure 7-1 shows a use case with four DS320PR410 are cascaded to read from single EEPROM, but the user can cascade any number of DS320PR410 devices in a similar way. Tie the READ_EN_N pin of the first device low to automatically initiate EEPROM read at power up. Alternatively, the READ_EN_N pin of the first device can also be controlled by a micro-controller to initiate the EEPROM read manually. Leave the DONEn pin of the final device floating, or connect the pin to a micro-controller input to monitor the completion of the final EEPROM read.

Figure 7-1 Daisy Chain Four DS320PR410 Devices to Read from Single EEPROM