TPS546C23EVM1-746: Not receiving ACK through PMBUS from either of the devices

Rahul Balakrishna

Part Number: TPS546C23EVM1-746
Other Parts Discussed in Thread: TPS546C23

Problem :

I am not receiving ACK through PMBUS from either of the devices addressed 27 and 36 (in decimal). I have an FPGA trying to emulate the master.

Setup :

I have pulled up Clock, Data lines (9,10 pins of PMBUS) to 3.3 V with 1Kohm resistors. DIOs from the FPGA are given to the Clock and Data lines with common ground(pin 6). I have verified the address byte using the DSO. I start the PMBUS command then I send the address byte (0011011 0 - along with 0 for write operation), I am not receiving ACK from the device (both 27d or 36d). I have powered the device with 6.5 V supply.

Please let me know if I am missing something and let me know the steps to debug the circuit.

Thanks in advance

Rahul

over 4 years ago

0 Peter James Miller over 4 years ago

TI__Guru 53295 points

Rahul Balakrishna

Sorry to hear that you are having issues communicating with the TPS546C23EVM1-746

A couple of things to check:

1) There are jumpers between the PMBus header and test-points, and the PMBus pins of the devices. Are these jumpers installed?

If the jumpers are not installed, the header and the test points are not connected to the TPS546C23 devices. Since you are attempting to access Address 27, you'll need to have JP1 and JP2 installed. If you are still unable to receive an ACK from the address byte, you can try using the TI FUSION Digital Designer and USB-to-GPIO dongle. The FUSION software will scan all of the addresses and provide a list of all connected devices with their addresses to confirm the addresses that the TPS546C23 are connected to.

If you are still having issues, please take an oscilloscope image of the CLK and DATA lines during the Address Byte