i.mx6q instructions failure

vladimirlegosta — Tue, 21 Aug 2018 12:23:36 GMT

Hello!

One of our custom boards did not started as expected when first turned on.
When jtag was connected, it was found that some CPU instructions were not working correctly.
Here is the result of the simplest test performed on the operating and non-working boards

(in u-boot, start.S, after save_boot_params ).

	good imx6		bad imx6
instruction	reg	value	reg	value
	r0	0x4 (Hex)	r0	0x4 (Hex)
	r1	0xd500 (Hex)	r1	0xd500 (Hex)
	r2	0x900000 (Hex)	r2	0x900000 (Hex)
	r3	0x800 (Hex)	r3	0x800 (Hex)
	r4	0x0 (Hex)	r4	0x0 (Hex)
mov r0, #0	r0	0x0 (Hex)	r0	0x0 (Hex)
	r1	0xd500 (Hex)	r1	0xd500 (Hex)
	r2	0x900000 (Hex)	r2	0x900000 (Hex)
	r3	0x800 (Hex)	r3	0x800 (Hex)
	r4	0x0 (Hex)	r4	0x0 (Hex)
ldr r4, =0xFFFFFFFF	r0	0x0 (Hex)	r0	0x0 (Hex)
	r1	0xd500 (Hex)	r1	0xd500 (Hex)
	r2	0x900000 (Hex)	r2	0x900000 (Hex)
	r3	0x800 (Hex)	r3	0x800 (Hex)
	r4	0xffffffff (Hex)	r4	0xffffffff (Hex)
ldr r1, =0x55555555	r0	0x0 (Hex)	r0	0xe1810400 (Hex)
	r1	0x55555555 (Hex)	r1	0xd500 (Hex)
	r2	0x900000 (Hex)	r2	0x900000 (Hex)
	r3	0x800 (Hex)	r3	0x800 (Hex)
	r4	0xffffffff (Hex)	r4	0xffffffff (Hex)
ldr r2, =0xAAAAAAAA	r0	0x0 (Hex)	r0	0xe1810400 (Hex)
	r1	0x55555555 (Hex)	r1	0xd500 (Hex)
	r2	0xaaaaaaaa (Hex)	r2	0xaaaaaaaa (Hex)
	r3	0x800 (Hex)	r3	0x800 (Hex)
	r4	0xffffffff (Hex)	r4	0xffffffff (Hex)
orr r3, r1, r2	r0	0x0 (Hex)	r0	0x8104d500 (Hex)
	r1	0x55555555 (Hex)	r1	0xd500 (Hex)
	r2	0xaaaaaaaa (Hex)	r2	0xaaaaaaaa (Hex)
	r3	0xffffffff (Hex)	r3	0x800 (Hex)
	r4	0xffffffff (Hex)	r4	0xffffffff (Hex)
and r4, r1, r2	r0	0x0 (Hex)	r0	0x8104d500 (Hex)
	r1	0x55555555 (Hex)	r1	0xd500 (Hex)
	r2	0xaaaaaaaa (Hex)	r2	0xaaaaaaaa (Hex)
	r3	0xffffffff (Hex)	r3	0x800 (Hex)
	r4	0x0 (Hex)	r4	0x8000 (Hex)

Tell me, can such behavior be related to
1. CPU failure
2. Board defects
3. something else
?

Thank You!

Re: i.mx6q instructions failure

igorpadykov — Tue, 21 Aug 2018 23:27:11 GMT

Hi Vladimir

one can check if processor power supplies are within allowable range using datasheet

i.MX 6Quad Applications Processors | Quad Arm® Cortex®-A9 |NXP

and i.MX6 System Development User’s Guide

https://www.nxp.com/docs/en/user-guide/IMX6DQ6SDLHDG.pdf

Try with other jatg debugger or script.

Bring up i.MX6 via JTAG

Best regards
igor
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i.mx6q instructions failure

Re: i.mx6q instructions failure