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TPS659121

abe eba
Prodigy 20 points

I'm testing the eval board TPS659121EVM and I'm unable to disable the DCDC1 converter via the AVS register over the standard-I2C interface.

Jumper settings:

CONFIG1 = 0

CONFIG2 = 1

Register values:

I2C_SPI_CFG (0x26) bit 0 = 0 (ie DCDC1_AVS control is assigned to standard-i2c interface)

DCDC1_OP (0x04) bit 6 = 1 (ie SELREG enables DCDC1 voltage control via DCDC1_AVS register )

DCDC1_AVS (0x05) bit 7 (ENABLE) is stuck to 1.  When I write a 0 to the ENABLE bit and read back the register value, the bit is still set to 1. 

I can change all the other bits in that register and I get the expected voltage scaling on the output of the DCDC1 converter.  I2C bus traffic shows I'm sending the correct data. 

Using the steps above I'm able to disable the other DCDC converters using their respective DCDCx_AVS registers.

Questions:

1) Any thoughts on other things I can try?

2) Who should I talk to about getting a custom OTP configuration?

  • 0
    TI__Expert 3740 points
    Ensure that the KEEP_ON bit for DCDC1 is set to 0 : Register 28h bit 2
    Ensure that the ENx_SETx register does not have DCDC controlled by one of the EN jumpers on the board
    Try disabling through the AVS register after checking the two suggestions above.

    These two bits will keep I2C from controlling the enable bit in the DCDC1 AVS register.
  • 0 in reply to Janice Escobar
    Prodigy 20 points
    Thanks!
    clearing EN1_SET2 (03h) bit 2 fixed it for me

    the KEEP_ON bit was already cleared (in fact it was the only one cleared compared to the other DCDC converters that I could successfully control). I changed this bit a couple times just to make sure, but It looks like this doesn't affect the ability to change the DCDC1_AVS ENABLE bit.