IMX6UL UART or USB serial downloader

[alubeiro]

Hi all,

We got a custom board based on a IMX6UL, which is not detected as an HID.

Is there anyway to know if the serial downloader is going through UART or USB?

Maybe any register or something?

Thanks and best regards

[Yuri · Accepted solution]

Hello,

  In serial downloader mode i.MX6UL boot ROM  checks activity on USB OTG1 and UART 1/2.

According to section 8.9.2 (UART) of the i.MX6UL RM : "The noise on UART RX data pad may
cause a “data ready” event reported by UART controller, and further cause ROM entering UART
serial download mode."

   I am afraid we do not have explicit external indicator to define if boot ROM is in serial downloader

mode, and what channel is used : USB or UART, except having proper activities of USB or UART.

Also JTAG debugging may be used to define what device USB or UART is active now.

   The fact of non-working USB boot mode (when properly configured BOOT_MODE[1:0] ) may mean,

the system does not start. Please check design using "Hardware Development Guide for the

i.MX 6UltraLite Applications Processor".

http://cache.freescale.com/files/32bit/doc/user_guide/IMX6DQ6SDLHDG.pdf

Have a great day,
Yuri

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