TPS65988EVM: TPS65988 is not sending the ACK after sending the "Register number" over I2C during the reading process.

Hello,

Would you be able to share a capture of your I2C transaction? 

Hi,

Please see the below Image. As you can see, On first 8 clocks after start pulse, PD controller sends ACK, After that master sent register address 0x00 after that No ACK received and the communication halted.

This waveform shows an ACK (SDA low) after the register address (at the 18th rising edge).

It's the register address not an ACK. Register address is 0x0. I also tried with 0x01. 

Hi Niket,

You can use the below as reference, but if you are wanting to read a register, you should be writing to the device address, putting the register address, and then reading the device address. 

Would also recommend increasing the delta between the clock sequences (8 clock cycles) 

The register address has 8 bits. The ACK is the ninth bit. The waveform shows 18 (8+1+8+1) bits.

Hi,

in the 8+1+8+1 sequence, the last 1 bit which is ACK from the PD controller is missing.

The first 8 bits are the PD slave address which is 0x20.

Then 1 bit is the ACK from the PD controller

Then 8 bits are the register address, which I want to read(0x00)

After sending the 8-bit register address SDA goes high and remains high but it should be LOW during the LOW period of the clock. That means the PD controller is not giving the ACK. 

If you see the 9th bit (after sending the PD  slave address) there is a high to low transition (for ACK pulse) but the same is missing at the 18th pulse(8(slave add)+1(Ack)+8(rgister_add)+1(Ack which is missing)). 

Yes, you are right I am doing the same thing. Please see the waveform I shared. The write bit is Low in that waveform which means I am doing the write operation first then giving the register address after that the PD controller is not giving the ACK.