Linux/AM4378: peripheral boot from UART

Marek Belisko

Part Number: AM4378

Tool/software: Linux

Hi,

I have gumstix poblano board with am4378 and it looks like it cannot enter to peripheral boot mode (printing CCCC on serial console and image can be sent over UART). I read about similar issue:

but errata shows that UART peripheral boot is broken only on rev. 1.1 (while is I decoded it correctly I have revision 1.2): AM4378BZDNI00. Is there some other problem or do I need to do something else to enter this mode? Thanks.

over 6 years ago

0 Kemal R. Shakir over 6 years ago

TI__Guru 55345 points

Hello Marek,

You need to setup your custom board's DDR, PMIC and serial console configs. Please, refer to this thread and perform the similar steps for your board.

Best regards,
Kemal

0 Marek Belisko over 6 years ago in reply to Kemal R. Shakir

Intellectual 330 points

Hi Kemal,

but IIRC for am335x when cannot find any bootable media it just to peripheral boot mode so I saw CCCC on serial console then can send over x-modem u-boot-spl.bin (which init DDR + rest of the system) and then again send u-boot.img. My problem is that if no bootable media is available (eMMC is empty + SD card is not plugged - other sysboot options are USB0, USB1 also not plugged) then I should see CCCC on serial console and this is printed by RBL (rom boot laoder) or am I missing something? Thanks.

0 Kemal R. Shakir over 6 years ago in reply to Marek Belisko

TI__Guru 55345 points

Yes, these 'CCCC's are printed by RBL only in UART SPL boot mode. The RBL doesn't print 'CCCC's when it tries to boot from eMMC, SD or USB0, USB1.

0 Marek Belisko over 6 years ago in reply to Kemal R. Shakir

Intellectual 330 points

So it means I need to update somehow my sysboot pins to be able to boot from UART? Thanks.

0 Kemal R. Shakir over 6 years ago in reply to Marek Belisko

TI__Guru 55345 points

Yes, you need to check your board's SYSBOOT setting, match these settings with the settings in Table5-10. SYSBOOT Configuration Pins in the TRM, and see if you have the UART0 listed in the Boot Sequence. If not, you will need to change your board's SYSBOOT settings and choose one which contains UART0 on it.

0 Marek Belisko over 6 years ago in reply to Kemal R. Shakir

Intellectual 330 points

OK thanks. Make sense.

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Linux/AM4378: peripheral boot from UART