Unable to debug S32K148 using PEmicro Multilink

[avulamallikarju]

I'm working on a prototype board with just S32K148 MCU along with a programming header to flash and debug code. What I have noticed is that upon powering the board, the RESET line always stays low. Due to this, I'm unable to flash code onto the MCU from S32DS by using a Multilink Universal FX debuggger probe from PEmicro where I get the following dialog:

It appears to me that the MCU is somehow constantly in RESET mode. I've tried using the Kinetis Recovery Utility but to no avail. I also tried to do a mass erase by selecting the appropriate option from the Debugger configuration of the IDE and that didn't seem to work either. From a hardware design standpoint, I followed the design guidelines document from NXP for S32K1xx devices. Therefore, I'm fairly confident that this may not be a hardware issue. However, I'm able to flash and debug the code on a S32K148 Evaluation Board with no issues at all. This makes me think if it has something to do when dealing with a blank MCU.

[danielmartynek]

Hello avulamallikarjun@bfusa.com,

The parts are shipped blank, therefore, it is expected that the MCU will be in a periodic reset due to core lockups when powered. But this should not be an issue.

Are there any HW differences between the EVB and your prototype?

Do you have more prototype? Please check all connections and reheat the MCU.

Could you measure the VDD power supply and the PTA5 reset_b pin with an oscilloscope?

Is the reset pin constantly low or is it being triggered periodically?

BR, Daniel

[avulamallikarju]

Hello Daniel,

Thank you for the response. The schematic of my target board is mostly similar to that of the EVB. However, in order to eliminate the variables in this issue, I'm using a different prototype board which has just the MCU populated (plus crystal and other necessary passives). In spite of trying on multiple prototypes, the RESET line stays constantly low whereas Vdd is rock solid at 3.3V.

Thanks,

Max

[avulamallikarju · Accepted solution]

Daniel,

I believe our HW engineer may have identified the issue. VDDA, VREFH and VREFL were found to be floating. In a different thread in the forums, it has been pointed out that this might cause the RESET line to be constantly low.

Thanks,

Max