topic Re: i.MX6: Native UART1 Communications? in i.MX Processors

i.MX6: Native UART1 Communications?

philhale — Tue, 08 Jun 2021 00:41:22 GMT

Will a out-of-the-box i.MX6ULL chip communicate via its UART1 upon powerup? Will it offer any type of bootloader command line interface? It did this with the EVK board, from what I remember. Could you burn the startup fuses using this boot interface?

Re: i.MX6: Native UART1 Communications?

Yuri — Tue, 08 Jun 2021 05:47:15 GMT

@philhale
Hello,

After power up i.MX 6ULL bootloader (in boot ROM) starts.
If there is no any boot image (say, on SD card) available,
the Serial Downloader can be used to download a program
image to the chip over the USB or UART serial connection.
This allows to load and run U-boot for further activities.

Serial Download Protocol (SDP), described in the Reference
Manual, is used by i.MX Serial Downloader.

Regards,
Yuri.

Re: i.MX6: Native UART1 Communications?

philhale — Tue, 08 Jun 2021 18:56:57 GMT

Yuri,

Thank you. Quick follow up question.

(a) Is the ROM internal to the i.MX6ULL? If the i.MX6ULL is the only device on a board and I connect to the UART1, can I possibly upload the operating system.

(b) Assuming that the above questiion (a) is Yes, will the UART1 interface allow me to set the fuses so the i.MX6ULL will boot via an attached SD Card?

In my situation, I only have access to BOOT_MODE0 and BOOT_MODE1. We accidentally left off all ability to modify the BT_CFG[0..7] / LCD_DATA[0..7] boot configuration straps. We also have the SD card connected to port SD2.

When I go into production, I will add the BT_CFG straps but for now, I need to get this system up and running to test everything running on the SD Card Yocto configuration.

Regards,

Phil

Re: i.MX6: Native UART1 Communications?

philhale — Tue, 08 Jun 2021 19:00:43 GMT

Yuri,

I am connected to UART1 with a USB-UART emulator at 115200. I should be seeing some activity on that port, correct? I mean, there should be some interface that will allow me to load U-Boot, correct?

Regards,

Phil

Re: i.MX6: Native UART1 Communications?

philhale — Tue, 08 Jun 2021 19:29:12 GMT

Yuri,

Two more things.

(1) I have read IMX6ULLRM, Section 8.2 "Boot Modes". It is still not clear whether Serial Bootloader mode will provide a human-readable interface.

(2) I DO HAVE a USB-OTG1 port connected. USB Type-A port.

Regards,

Phil

Re: i.MX6: Native UART1 Communications?

Yuri — Wed, 09 Jun 2021 08:06:42 GMT

@philhale
Hello,

The Serial Bootloader does not provide a human-readable interface.
It can be used to load and run, for example - U-boot with human-readable interface.

Please refer to the user's guide how to start with i.MX6 board.

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

Demo image:

https://www.nxp.com/webapp/Download?colCode=L5.10.9_1.0.0_MX6UL7D&appType=license

Regards,
Yuri.

Re: i.MX6: Native UART1 Communications?

Yuri — Wed, 09 Jun 2021 08:10:04 GMT

@philhale
Hello,

yes, the mentioned boot ROM is located internally into the i.MX6ULL.

To burn the fuses U-boot should be used.

https://imxdev.gitlab.io/tutorial/Burning_eFuses_on_i.MX/

Regards,
Yuri.

Re: i.MX6: Native UART1 Communications?

philhale — Tue, 15 Jun 2021 16:34:45 GMT

Thank you!

Phil