AM335x : TI employees, where can I get the ROM Bootloader source code/symbols?

TI has no plans to release source for the ROM code.

Regards,
Paul

Ben, unfortunately, we cannot release ROM source to customers.  Let us know what your boot issue is and we can guide you to debug.  I've written up some common tips here to get started

http://processors.wiki.ti.com/index.php/AM335x_board_bringup_tips

Regards,

James

I've read that many times, friend. And I've read the boot vector information.

What I have is an AM335x that is set to boot SPI first. When the SPI load fails (the flash is unprogrammed) I attempt to stop the processor with the debugger (XDS100/ CCSv5.4)

The processor stops in what appears to be unprogrammed space in the ROM bootloader (0x24bfa) but the processor has not trapped (still in mode 0x13). 

So, I'm left to guess what the bootloader code is at that location.

Sure you want us fighting with one hand tied behind our backs?

Can't you at least release some symbols for key places in the code to set breakpoints? I'd like to be able to stop at the point that the SPI flash is evaluated (I know it is going to fail, being unprogrammed).

Thanks!

Ben.

Hi Ben,

0x24bfa is in a routine that is performing a UART read, so it looks like it is attempting a UART boot.  So this is expected behavior if UART follows SPI in your boot order. 

Would love to be able to give you symbols too, but I'm strapped with doing that as well.  Here are some symbols which may help. 

0x231E0 SPI Initialize

0x23230 SPI ReadSectors

The Initialize routine sets up clocks and pinmux, and configures the SPI module registers.  ReadSectors enables the channel, send commands to read, then closes the channel.

Regards,

James

Hi,

Since ROM code is not open to all , we are unable to find information related to USB boot option . There is no documentation to help boot from USB option .

How we can load the MLO and U-BOOT in AM335x though USB port? I know it can be done by SD card/serial port  and it will load to eMMC/NAND but if I have a USB stick/External HDD/USB connected to host, how can MLO and UBOOT be fetch through USB port and able transfer directly to eMMC/NAND.

Hi Gokul,

Please read section 26.1.8.6 from the AM335X TRM Rev. K. USB boot when the AM335X USB port is in Host mode is not supported.

Yes, this is described in: http://processors.wiki.ti.com/index.php/AM335x_U-Boot_User's_Guide

JJD said:

I've written up some common tips here to get started

http://processors.wiki.ti.com/index.php/AM335x_board_bringup_tips 

Good job James, thank you.

One item is missed there, addressing a hard case when there is no "CCCC" output on the UART0 at power up, while both power sequence, and boot mode pins state are correct. I'm about the EMU0 pin.

It is not explicitely documented, and only few hints could be found on forums. (I happened to run into this trouble, and therefore I'm here)

The EMU0 pin should be left open: there is an internal pull-up, in the am335x chip, or (recommented) pulled up externally.

Sviss,

The http://processors.wiki.ti.com/index.php/AM335x_Schematic_Checklist#JTAG.2FEmulation has a link to http://processors.wiki.ti.com/index.php/XDS_Target_Connection_Guide#Target_Connection_Design where EMU0/1 pins are discussed.

Currently using beaglebone black to emulate my project requirements, and not able to use micron boot0 and boot1  boot partitions for emmc booting, instead using user partition.

As you have the privilege to look into the black box :-) , please let me know if bootrom supports booting from the boot0 partition of the emmc ??  

The boot ROM only boots from the user area. It does not boot from boot0 or boot1.

Steve K.

Harsha Kiran said:

Is there a particular reason why the ROM code cannot access boot0 or boot1?

It just isn't implemented in the omap4-generation ROM used by the am335x.