ZHCSQD1 August 2022 DS320PR810
PRODUCTION DATA
The DS320PR810 can also be configured by reading from EEPROM. To enter into this mode MODE pin must be set to L1. The EEPROM load operation only happens once after the device's initial power-up. If the DS320PR810 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 DS320PR810 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 DS320PR810 has finished reading from the EEPROM successfully, it will drive the ALL_DONE_N 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 DS320PR810 registers, then it must support arbitration.
When designing a system for using the external EEPROM, the user must follow these specific guidelines:
Figure 7-1 shows a use case with four DS320PR810 to implement a PCIe x16 configuration, but the user can cascade any number of DS320PR810 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 ALL_DONE_N pin of the final device floating, or connect the pin to a micro-controller input to monitor the completion of the final EEPROM read.