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Dead MCU on custom hardware - iMXRT1021 100pin

Question asked by Chris Cowdery on Aug 1, 2019
Latest reply on Aug 5, 2019 by jeremyzhou

We are trying (and so far failing!) to bring up our custom hardware. It has an iMXRT1021 in 100pin form.

We have two tests:

1. SWD interface via J-Link Commander. Can we 'connect' to the Core?

2. UART interface via LPUART1, SDPHost.exe. Does it respond to sdphost -p COM5 -- error-status ?

We have verified both techniques on the EVK, so we know what we expect to see.

But our hardware does not respond to either.

We have a minimum build, which is MCU, Power supplies, and configuration / boot mode pins hard wired (all cfg to 0V, and Boot Mode to Serial Download). We have the 24MHz crystal, but not the 32KHz crystal. POR pulled high. No external Flash, so nothing to execute. So pretty simple!


We have verified:

1. Power Supples - 0V, 3.3V, DC-DC converter = 1.1V, NVCC PLL=1.1V

2. 24MHz crystal not oscillating (not sure if it should do so).

3. Connections of SWD and LPUART, definitely the correct signals on the correct pins.

4. Pinout against datasheet.

5. Measuring the voltage on each pin to check it is as expected (mostly power supplies and configuration pins)

6. POR is high.


We are now going to hack an EVK to have the same configuration as our hardware (lift processor pins) to see if we can make it behave the same.


But - are there any errors in the documentation?, or special features we need to be aware of?, or is there a prerequisite for operation that is not listed above?