Looking for information on OMAP5912

[helltron]

Hi chaps! I'm trying to get into TI OMAP processors, especially 5912. I've got a radio navigation board here, which has such a processor and i have it for spare to learn and do some funny stuff with ;-)
It is equipet with an 64MB NOR-Flash (S29GL512) and and 32MB SDRAM. It also has an SD-Card interface and of course JTAG.

I'm looking for some helping hand or tipps, because all i find for now is from datasheets and very hard to understand for a newbee like me.

I try to understand the bootstrap process and how to get my hands on it. Maybe, in a far future, to install a Linux on the device ;-)
I've managed to connect to the target via JTAG and read the Flash. After saving the dump i erased the Flash, but it seems to have sector-protection on it. The first sector is not eraseable (simply keeps it's contents). I assume to find the 2nd stage bootloader here. I guess the 1st stage bootloader is inside the SOCs internal, small ROM code (64 kb, if i read correctly) and all it does is to read some signals to determine boot method by sampling some external IO-Ports on powerup. They will tell the code on which source the 2nd stage bootloader is to find and where to load it to. Also the 2nd btl is very small (2kb or so).

I guess i have found the bootloader code, but can i disassemble it and do some single stepping from poweron? The ARM926EJ-S processor is running in Little-Endian, right? Also it supports thumb-mode, but don't know if it does in boot mode? Found an online disassembler at https://onlinedisassembler.com. If i get it correct the ARM processor uses ARMv5TE instruction set.

Thanks in advance!

[bhytrjerfve]

Hi, did you figure out anything? I have a pdf with very good documentation on mostly the physicals of the OMAP5912 chip. I was thinking about trying to get linux running on it too, and i have quite a few devices to test on if i fry anything (they have a screen and keyboard built in so its pretty good already in terms of usability). I also have an update tool which seems to flash the entire ARM cpu and the vocoder chip. Maybe there is something interesting in the files of that tool.

[thinkfat]

I think you have figured out a lot on your own already. I'm not sure if I can provide much help on the OMAP5912, back in the days I was very familiar with the OMAP5910 as it was used in one of the products the company I worked for had developed (https://en.wikipedia.org/wiki/Archos_PMA400).

The OMAP series of chips is quite well supported by Linux nowadays, the same OMAP chip was used in a number of Nokia products I believe. Despite the odd name, the 5912 is actually an OMAP1 device, not an OMAP5. The best help you can get I think is by downloading the Technical Reference Manual (TRM), TI document SPRU762B, and go from there. It should contain a pretty good description especially of the boot process and its options.

Beware, though, that this document is only the public version of the TRM and there exist other versions that contain much more information. But you'll only get access to those if you have a business case and hand over some "I'm serious!" money.

I'm not sure what made you pick such an odd chip, it's not exactly something that would lend itself easily to a beginner. There are many other, equally interesting but more beginner-friendly chips out there.

Best of luck, though.

[bhytrjerfve]

Thank you! I will take a closer look at what you sent when i get home. At my job we have a box full of "broken" Hytera DMR radios (PD685 and X1P). The only thing that is broken on those is the external accessories contact, the copper pins are oxidated because of contact with seawater (which is expected as we sell them to seafarms). Therefore they are deemed useless for work-purposes, so we are free to do whatever we want with them.
I accidentally found that PDF on the work onedrive, and when i saw how well documented it was i got some hope to be able to do something. Therefore i have chosen them as my project, and the goal is to run doom or smth on them Yes, i agree that its not really a beginner friendly project (especially with the odd choices Hytera has made), and i have practically no experience higher than an ESP32.
My plan was to first get the ARM processor up and running and then try to interface with the DSP. If i'm able to somehow extract the files from my upgrade tool, i can probably figure out running linux and interact with the audio chip.

[thinkfat]

Getting the ARM9 up will be relatively easy, as it is the boot cpu of the system. The DSP has a quite specific interface to the application CPU, but it is a nice, relatively powerful core, at least it was in 2005, when the OMAP1 platform was fresh. You will definitely need some SDK from TI to get it up and running. I'm not sure if these components are public nowadays.

[RoGeorge]

Try searching for 'OMAP5912 devboard' from TI.  You may find kits with intro docs and code examples, e.g. https://elinux.org/OSK.

Beware that meanwhile the TI compilers have become freeware, you can download the full license key for free, from TI.  IIRC the OMAP line was discontinued/obsoleted long ago.

[thinkfat]

Try searching for 'OMAP5912 devboard' from TI.  You may find kits with intro docs and code examples, e.g. https://elinux.org/OSK.

Beware that meanwhile the TI compilers have become freeware, you can download the full license key for free, from TI.  IIRC the OMAP line was discontinued/obsoleted long ago.

I thought so, too, but it seems that the OMAP5912 is an active device. I'm not sure who would use it nowadays, though. It has a single ARM9 core and an aging C55x DSP core. Good enough for MP3 decoding.