Other Parts Discussed in Thread: TPS6594-Q1
We have an LP876441B1RQKRQ1 PMIC on our new design PCB which is not responding with data when we read the I2C.
We measured VCC=5.0V, VIO=3.3V, VOUT_LDO=1.8V, initially there was some residual voltage on one of the BUCK outputs, but we have reduced that to 0.0V
When we perform I2C read to device ID = 0x4c, 0x4d, 0x4e, 0x4f, 0x13, we see ACK on the first 3 bytes, and NACK on the 4th byte (as expected). When reading all other device ID (those not listed here) we see NACK after the 1st byte.
When reading device ID = 0x4c and address = 0x01, we get 0 rather than than expected 0x86. We were also unable to change the I2C device ID register, as we were able to do on the EVM.
We are able to read/write and program the NVM on the same part on the LP8764x-Q1 EVM with no problems.
This was all done using the Register Map page of the PMIC GUI v4.0.0. We also tried accessing I2C from a Total Phase Aardvark device running at 10 kHz.
Reading all 0 values for all register reads seems problematic to initializing the NVM, because we are unable to confirm the NVM unlock state.
One item that is unclear from reading the documentation, is if the ENABLE signal is required internally to transition successfully from NOSUPPLY, LP_STANDBY, INIT, BOOT BIST states into the Mission States. And if so, how is it possible for a new unprogrammed part to support this, since ENABLE is a non-default setting for the GPIO4 pin. Is it possible for us to program a brand new unprogrammed part on our custom PCB with I2C like we are trying to do?
