LS1020A starts not constantly

[ilyaminaev]

Hello. I created a motherboard with a 1020A processor. and when the board is turned on, the processor behaves differently each time. Often there are situations in which the processor does not respond to PORESET_B. This happens when the line RESET_REQ_B  produces 0. When   RESET_REQ_B  1 starts, the processor starts abnormally after PORESET_B, it is loaded from the SD card. But the processor starts randomly. What could be the problem of such impermanence?

[alexander_yakov]

Please check if TRST pin is connected as recommended in LS1021A Design Checklist, Figure 32

LS1021A Design Checklist is available for download from LS1020A page, "Documentation" tab:

https://www.nxp.com/products/processors-and-microcontrollers/arm-based-processors-and-mcus/qoriq-lay...

Have a great day,
Alexander
TIC

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