Using certain GPIOs on MIMXRT1042XJM5B results in near-bricked board

[rtborg]

Describe the bug
I have a custom PCB with MIMXRT1042XJM5B. When I try to use specific GPIOs as outputs, the application crashes and the debugger can no longer connect. The NXP UART bootloader also cannot be invoked. The only solution I've found so far is to erase flash on board with external tool.

Board overlay file:

/ {
	leds {
		compatible = "gpio-leds";
		board_green_led: led_1 {
			gpios = <&gpio1 20 GPIO_ACTIVE_LOW>;
			label = "Board Green LED";
		};

		board_red_led: led_2 {
			gpios = <&gpio1 21 GPIO_ACTIVE_HIGH>;
			label = "Board Red LED";
		};
	};

	pins {
		compatible = "gpio-keys";

		can_stb: can_stb_pin {
			label = "CAN STB";
			gpios = <&gpio3 26 (GPIO_ACTIVE_HIGH)>;
		};

		power_5v_en_pin: pwr_en {
			label = "5V PWR EN";
			gpios = <&gpio1 17 (GPIO_ACTIVE_HIGH)>;
		};

		iso_pwr_en_pin: iso_pwr_en {
			label = "ISO 5V PWR EN";
			gpios = <&gpio2 31 (GPIO_ACTIVE_HIGH)>;
		};

		tft_pwr_en_pin: tft_en {
			label = "TFT PWR EN";
			gpios = <&gpio2 26 (GPIO_ACTIVE_HIGH)>;
		};

		tft_led_pwr_pin: tft_led {
			label = "TFT LET PWR";
			gpios = <&gpio3 14 (GPIO_ACTIVE_HIGH)>;
		};
	};

	aliases {
		boardgreenled = &board_green_led;
		boardredled = &board_red_led;
	};
	
};

The issue appears when I try to initialize the last two GPIOs: tft_pwr_en_pin and tft_led_pwr_pin. When I comment relevant lines, the rest of the code works with no issues.

To Reproduce
See attached files.

Expected behavior
Code should not put the processor in unrecoverable state.

Impact
Showstopper.

Logs and console output
No logs whatsoever; the crash happens immediately with no output.

Environment (please complete the following information):
Linux 6.5.1-060501-generic
zephyr-v3.5.0-3850-g8785438d31

zephyr.txt
main.txt

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[DerekSnell]

Hi @rtborg ,
I converted this to a discussion until we have more evidence that this is an issue with Zephyr.

I reviewed those two GPIO pins, and nothing is apparent to me that they would cause issues with execution or booting.

Since this is your custom board, have you confirmed this is not an issue specific to your board? Do you have the MIMXRT1040-EVK board? If so, can you try testing these same 2 GPIO pins on the EVK to see if it has the same issue? I see on that EVK, GPIO_B1_10 is used for ENET_TX_REF_CLK, and GPIO_SD_B0_02 is used as WIFI_SDIO_D0. So it seems the EVK should not have an issue using those two GPIOs.

Since your board uses these to enable the TFT power, have you confirmed the power supply to the MCU is unaffected when you try to use these GPIO? Have you already tried using a debugger to what happens in the application, and where exactly it occurs? Like do any faults occur within the application?

Let us know what you find.

[rtborg]

Hi @DerekSnell,

I managed to trace the root cause - it was a hardware fault.