AM2434: Reset by nREST of XDS110

Hi Hideaki-san,

Since EMU0, EMU1, and TRST have different meanings that direct device boot and behavior upon debugger attachment, I'm not sure ARM 10-pin is suitable for AM2434. I'm checking internally if these pins can be hardcoded, or need jumpers, or need connection to XDS. 

Please see a snapshot from the TRM:

Regards,

Stan

Regarding the pending questions:

Hideaki Matsumoto said:

hey would like to connect pin 10 (nRESET) to pin A5 (MCU_RESETZ) of the AM2434 to enable system reset while the power is on.

MCU_PORz is preferred since it is a fundamental reset. MCU_PORz is the pin asserted by XDS via nRESET on the EVM

Hideaki Matsumoto said:

Do they need to insert a Schmitt trigger in the circuit, as is done on the evaluation board ?

No, if no push-buttons or pin headers on this path.

Hideaki Matsumoto said:

If the nRESET is connected directly from the XDS110 without a push button, are there any reference designs or connection examples available ?

Firstly nRESET needs an on-board pullup since it is an open-drain output coming from the XDS:

Second requirement is to have a fast buffer to shape out the rising edge. In the EVM, for example there is 2 AND buffers collecting PORs from different sources. You may have more or less sources. Please refer also to the remarks on the screenshots. 

Hideaki Matsumoto said:

(Pin B6: TRSTN is planned to be pulled down.)

This is also part of my concerns. I don't know if debug session will ever start with TRST hardcoded to 0.

Regards,

Stan