AM1808 boot modes

Miguel,

This looks helpful.  Thanks very much.

Peter

I have read through the link in the previous post and am still not clear.

The link below is found on the link you posted.  Under the section "Rebuilding U-Boot" explains that you need to install the Code Sourcery tools and download the DaVinci-PSP. It also has a section "Rebuilding the ARM Side User Boot Loader"

LINK1: http://processors.wiki.ti.com/index.php/GSG:_Building_Software_Components_for_OMAP-L1/AM1x

That link sends you to the "Linux PSP package" link below.

LINK2: http://processors.wiki.ti.com/index.php/GSG:_Installing_the_Software_for_OMAP-L138#About_the_PSP_package

Which has a "See attention note at top of page" which instead directs you to this link:

LINK3: http://software-dl.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/dvsdk/DVSDK_4_00/latest/index_FDS.html

This is essentially the download page for DaVinci SDK DVSDK_4.02 4_02_00_06.

To get at the source code I installed the exact version of Code Sourcery as described, then installed the DaVinci SDK.  After that I have access to the entire SDK.  Digging down a few levels there is a folder u-boot-2009.11-psp03.20.00.14   I used Code Sourcery to compile with the target da830evm_config as described in LINK1.  I get 5 u-boot files (u-boot, u-boot.bin, u-boot.lds, u-boot.map, u-boot.srec).  Further down LINK1 there is "Generating ARM AIS File for OMAP-L138" which shows a windows AISgen.exe where you point to "ARM Application File"   The example has "ubl-nor.out" as one example which is the output of the Code Composer Studio UBL Project from the SDK.

Question:

AISgen.exe is a windows executable which looks to me generates an image which conforms to the AIS Format described in "Using the AM18xx Bootloader" spraba5b.pdf.  I took u-boot.bin and gave that to AISgen with options to boot off RS-232 on the EVM (with my current revision of the EVM it would be UART2,d800k006,ARM,24MHz) to generate a Boot_UART_Then_SD_Card.bin.  Since it is a bin file, you have to specify an entry point, I used 0x80000000(OnChip RAM). I used the OMAP-L138 UART Boot Host application as described in spraba5b to connect the PC to the RS-232 on the EVM and gave it the Boot_UART_Then_SD_Card.bin.  Installed in the SD Card connector is the unmodified SD Card that came with the EVM.  The EVM comes configured with UBL in the SPI Flash which loads in the SD Card.  I changed the jumper settings to boot off UART2. When I power on the EVM is does talk to the Boot Host application and it looks like the file gets downloaded into the CPU.  It should then run this code and read the uImage on the card and load in the demo application, but it doesnt look like that is happening.

I have verified the UART Boot process works by using the example LED project located here:

LINK4: http://processors.wiki.ti.com/index.php/Boot_Images_for_OMAP-L138

Do you expect that the process I described should boot the system?  I did not use the UBL project but I believe the AISgen should be handling that part.

Hi Pietro,

I've not the answer but some suggestions that hopefully could help. If you are working on AM1808 I think you should build u-boot with da850 profile and not da830. In my case the u-boot binary is larger than On-Chip RAM at 0x8000000 (128KB, if not wrong), so I need to load it into mDDR (of course this requires AIS script to configure and setup mDDR). Finally maybe some changes could be required into u-boot (eg: default configuration will read environment from SPI Flash) to start from UART.

Hope this help.

Another question I have is has anyone used the UBL (User Boot Load) project found in the DaVinci SDK to configure the AM1808 and load in the U-Boot. 

Or has anyone used the AISgen GUI with a U-Boot binary to do the same thing? 

If someone has done both I am trying to understand the pros and cons of those methods.

I am trying to develop a very small program possibly based off of the UBL project.  I want to set up PLL, mDDR etc and run some diagnostics on the mDDR before I continue the boot process and load in the U-Boot or uImage.  Anyone have suggestions on this?   Thanks.

I have used AISgen GUI with a U-Boot binary to skip UBL need in booting phase: ROM Boot Loader reads AIS script and then load and execute U-boot.

I'm not an expert, but I think that if all you need is PLL, mDDR and other things that can be done with AIS scripting (have a look at the documentation), you do not need UBL. The advantage could be boot time and/or memory space, but don't know how much. UBL give you more flexibility on booting schemes and the possibility to execute actions you cannot with AIS: if you want to run mDDR diagnostics I think you need something like UBL.

Regards, Max