I am working with a Hercules TMS570LS0432 microcontroller, attempting to make a custom bootloader. In order to do this I need to use the F021 API, which is where I've encountered problems.
The issue I am having is that upon calling Fapi_setActiveFlashBank an undef exception occurs and program execution goes to the entry for the undef exception in the interrupt table (0x04). Because the F021 lib is already compiled, I can't tell where the exception is occurring, but in terms of assembly (which I can see), it almost always fails on an ANDS instruction, but sometimes on an LDR instruction. I don't know if this is useful information, but perhaps it can help.
Regarding my setup:
- I am using HALCoGen, Keil uVision5, and have properly imported the F021 lib.
- I have correctly initialized the HCLK (80MHz) and data wait states (1).
- I am calling Fapi_initializeFlashBanks prior to the failing Fapi_setActiveFlashBank call. The Fapi_initializeFlashBanks call appears to succeed.
I currently have a few ideas based on other posts in the forum, but I feel like I need a little extra guidance to point me in the right direction. They are as follows:
1) I am not copying the F021 API from Flash to RAM. The F021 API spec mentions that the F021 API must execute from a different bank than it interacts with. However, it does not mention anything about how to copy the API to RAM from Flash in order to achieve this.
I found the place where this was done in the the TI bootloader for TMS570LS0x32 app note. They have an assembly function called _copyAPI2RAM_, but it has dependencies/references that I cannot find in the given files. I also saw another way to do this that someone wrote about in a forum post here: https://e2e.ti.com/support/microcontrollers/hercules/f/312/t/284120.
I feel like this is the most likely cause of my problem.
2) Could there be a conflict with compiling my code in ARM mode while the F021 API is compiled in Thumb mode? I have enabled ARM/Thumb interworking in Keil.
3) A third option that others have posted about is compiler optimization, and that compiling with no optimization fixed this problem. However, I do not think that is the issue as I have tried all the available compiler options and seen no difference.
Can anyone think of any other causes? Please let me know if you need any other information.
Thanks in advance for any help!
Gawan
