Hi,
We have developed our own custom C6748 board for one of our products. We are using the following software components:
- DSP/BIOS 5.41
- CCS 5.2
- Codegen tools 7.3.4
- AISgen 1.9
- Modified version of the CCS NORWriter flasher app that came with OMAP-L138_FlashAndBootUtils_2_40
Our application is now nearing completion, and we need an efficient way of booting our image. Given our *.out file, I have managed to generate a *.bin image with AISgen, which is then written to flash using the modified NORwrite app. However, we found that the initial image did not boot. The reason for this is that we configured the PLL for the maximum CPU frequency (456MHz) in AISgen, but due to hardware limitations the core voltage is still somewhere below 1.3V when the DSP attempts a NOR boot and consequently the operating point is undefined (because the PLL is configured for >100MHz), which is why the boot then fails.
The simplest solution is to initially configure the PLL in AISgen for <100MHz, and then just reconfigure the PLL in the application itself for 456MHz. However, the problem with this, is that it then takes forever to boot the actual image, which is unacceptable from the user's perspective.
The better option is thus to write a secondary bootloader, which initially delays for a few milliseconds to allow the core voltage to become stable at 1.3V and then reconfigure the PLL for 456MHz and continue to copy the main application image from flash to RAM and then branch to the main application.
This brings me to my questions:
1) I'm assuming I will/can only use AISgen to prepare the image for my secondary bootloader?
2) Can my secondary bootloader also be a DSP/BIOS application?
3) How should I prepare the image of my main DSP/BIOS application, given the *.out file? I am assuming I should use the hex6x.exe utility to generate some HEX image to be written to flash? I am aware that section 11 of this document http://www.ti.com/lit/ug/spru186w/spru186w.pdf, provides the details of hex6x.exe, but since I'm inexperienced with using this utility, I would really appreciate some pointers as to which format to use.
Your help would be greatly appreciated!
Kind regards
Reinier