Can't launch TinyRex. Need advice of red and green LEDs

[eugene128]

Hello.

We're using TinyRex Solo and we've produced some baseboard for it with all needed power levels (in accordination with datasheets and BSPs). TinyRex is configured to boot from SD (by manufacturer).

When to power ON without connected serial debug cable, the red LED lights up on TinyRex, custom baseboard together TinyRex are consuming 250mA 5V (constantly in time).

When to power ON with connected serial debug cable (RX,TX,GND):
1) red LED lights up
2) green LED lights up (for several seconds)
3) then green LED lights down (for several seconds)
4) then green LED lights up, again (for several seconds)
5) then green LED lights down, and doesn't light up until power hasn't been resetted.
When green LED is lighting, total power consumption (custom baseboard+ TinyRex) grows up to 20% (from 250mA to 300mA).

We're trying just to launch standard booting program and get access from PC's through serial debug.
But I'm not seeing any data on my debug console (it is just empty).

In accordination with datasheet:green LED - power
red LED - user's LED
I'm a bit confused, because green LED is lightning up only if RX,TX are connected.(in that time same connection works fine with OpenRex).

Does somebody have any ideas whats can be wrong? At what moment should green LED to light up and at what moment should red LED to light up, and what do they mean?

Thanks!

[robertferanec]

Interesting.

This looks like power or reset problems. GREEN LED is connected to POK_SYS (Power OK signal) and will get ON when all the module powers and reset are OK. So the GREEN LED should be always ON. Red is User Defined and can be controlled by software.

Double check if all the powers are ok, double check RESET.

PS:
I have seen many times that current leaking through serial console may sometimes prevent boards from booting up or cause unpredictable behavior.

Have a look at our OpenRex board, page 24 - that is the way how we isolated the console:
https://www.imx6rex.com/wp-content/u...Production.pdf

[eugene128]

Thank you for your hint, will recheck power/reset on our board.

[eugene128]

Hello. We've checked it.

But when TinyRex has been ran without serial-cable, we are still watching red LED.
Looks like it indicates the power ON (not user's event).

Could you check, please, is red LED placed physically on the right place on TinyTex?

[robertferanec]

It is the right place. Did you measure RESET?

[eugene128]

Could you clarify, please, the name of the RESET pin? (Actually I'm a bit confused)
If you mean SYS_POKn and SYS_RSTn, then we didn't touch them and left both of them disconnected on our board.

Actually we didn't out any additional pins on our custom board.
Only needed power pins (in accordination with datasheet), LAN and RX,TX,GND (for serial debug).
For serial debug we've only 3 pins: RX,TX,GND (that connection works fine with openrex).

Now (after power ON) we're watching green and red LEDs are pulling up constantly, also are watching constant level 3V3 on RX,TX on TinyRex (without any data signals) and 3V0 on the testpoints PMIC_ON_REQ and ON_OFF (6 and 8 PINs of J2).

[robertferanec]

What are you booting up from if you have not connected any pins, just LAN and UART?

[eugene128]

in that time we no need to load kernel, we need just to get access to uboot program through uart.

Also uboot can load kernel through LAN (in future we add usb-otg to our board, maybe).

[robertferanec]

Where is your uBoot stored?

[eugene128]

Sorry, my mistake.

We've connected POK to power signal, and now green LED lights up when power ON.

Also we've SD3 on our board (like at page 11 "MicroSD Slot" of "iMX6-TinyRex-Baseboard-Lite-V1I1-Schematic.pdf"
And efuses configured to SD3 by manufacturer.
As I understand right, TinyRex should find uBoot and Kernel on SD-Card, if all connected right?

[robertferanec]

Also we've SD3 on our board (like at page 11 "MicroSD Slot" of "iMX6-TinyRex-Baseboard-Lite-V1I1-Schematic.pdf"
And efuses configured to SD3 by manufacturer.
As I understand right, TinyRex should find uBoot and Kernel on SD-Card, if all connected right?

- perfect, yes, try to boot up. Please, let me know if that worked

[eugene128]

Works fine now. Thanks for help!

[robertferanec]

Fantastic!