DS90UB9702-Q1: How can the I2C channel passthrough between the 9702 and the 935 be achieved through FPGA configuration in the 9702 + FPGA + 935 architecture?

Hi Tianmeng, 

For pure I2C passthrough, enable I2C passthrough all on both UB9702s in register 0x58[7] for the selected port (selected in register 0x4C). 

If the same strap address for the UB935 is used on the test board and the camera. Then I2C passthrough all can not be used in this case as transactions for the camera will be responded to by the test board serializer as it is the first in the chain. 

See below example to set up communication with the camera on the Orin side: 

#  des addresses
des_9702_0 = 0x7A
des_9702_1_addr = 0x60
des_9702_1_alias = 0x60
# 935 addresses
ser_935_0_addr = 0x30
ser_935_0_alias = 0x94
ser_935_1_addr = 0x30
ser_935_1_alias = 0x96

# 9702-0 config
# select rx port 3
board.WriteI2C(des_9702_0, 0x4C, 0x38)  
board.WriteI2C(des_9702_0, 0xB0, 0x10) 
# set 971 address/alias
board.WriteI2C(des_9702_0,0x5B,ser_935_0_addr) #ser_addr 
board.WriteI2C(des_9702_0,0x5C,ser_935_0_alias) #ser_alias
# turn on i2c passthrough
board.WriteI2C(des_9702_0,0x58,0x5E) 
# 9702-0 target config
# Only the devices on 9702_1 ports[0:2] are programmed due to a limit of 8 target_id/alias registers per port
# If you need to communicate to port 3 devices, modify one of the 935 and sensor configs to include port 3
# For example, replace target_id[3] and target_alias[3] with the 935 address/alias on port 3, and replace target_id[6] and target_alias[6] with the sensor address/alias on port 3
board.WriteI2C(des_9702_0,0x5D, des_9702_1_addr) # target_id[0]
board.WriteI2C(des_9702_0,0x65, des_9702_1_alias) # target_alias[0]
board.WriteI2C(des_9702_0,0x5E,ser_935_1_alias) # target_id[1] 
board.WriteI2C(des_9702_0,0x66,ser_935_1_alias) # target_alias[1] 

# 9702_1 config
# select rx port 0
board.WriteI2C(des_9702_1_alias, 0x4C, 0x01) 
board.WriteI2C(des_9702_1_alias, 0xB0, 0x04)
#turn on i2c passthrough
board.WriteI2C(des_9702_1_alias,0x58,0x5E) # I2C passthrough = ON
#set 935 address/alias
board.WriteI2C(des_9702_1_alias,0x5B, ser_935_1_addr) # ser_addr
board.WriteI2C(des_9702_1_alias,0x5C, ser_935_1_alias) # ser_alias

Best,

Zoe

Hi Zoe

    Are the addresses of IIC devices all 8 bits when configuring them? We will find some time to verify it next week!

    Best regards,              

Hi Tianmeng, 

Yes, these are the 8-bit I2C addresses being used in the script example. 

Best,

Zoe

Hi Zoe

    
    Configure the 9702 for the orin and the test board respectively according to what you said. The orin cannot find the addresses of any devices on the test board. Is 0x7A the I2C device address of orin?

  Best regards,    

Hi Tianmeng, 

The IDX values in the first few lines will need to be configured based on your application. 

Best,

Zoe