2020-05-06 08:35 AM
Hi!
I have an external sram connected to a STM32H743. It has a 16 bit wide data bus.
I started a memory test and got lots of errors. So i had to look at the data in the sram with STM32CubeIDE 1.30.
For example:
I fill the complete memory with 0xFFFF. (no problem)
I'm writing 0x0000 at address 0x60001000. (no problem)
I'm writing 0x0000 at address 0x60001002. (no problem)
...
I'm writing 0x0000 at address 0x60001020. The data are set to 0x0000 at address 0x60001022, 0x60001024 and 0x60001026 too. :(
If i start with a higher address the error is at the address plus offset 0x20 :\
c++ code looks like:
*reinterpret_cast<uint16_t volatile*>(0x60001000) = uint16_t(0);
*reinterpret_cast<uint16_t volatile*>(0x60001002) = uint16_t(0);
...
FMC bank1 is set to sram (0) and 16bit width (1). Write FIFO is disabled. Data cache is disabled.
The data inside the ram is also not correct without starting the ide.
Why does the FMC generate four Writes? Do I have to change the configuration of AXI Target 5? Is there another fifo or cache?
Can anybody give me a hint?
Kind regards
Daniel
2020-05-07 04:56 AM
> And do you have the perseverance to get to the root of it?
Yes, I can be quite stubborn, especially if it happens in a project that we intend to sell to real customers. Problems like that can turn them into angry customers in the best case, and me into an unemployed man in the worst case.
> I prefer to be in control of my controllers.
Sometimes we have to make compromises. It gets several orders of magnitude worse in the MPU world.
2020-05-07 06:08 AM
> Yes, I can be quite stubborn
I never doubted that. I asked the wrong question. What I really meant above, do you offer to volunteer to investigate this item deeper? Note that this is an unfair request: myself said above I won't.
>MPU world
I'm acknowledging the methods of that world, but they leave me unimpressed.
JW
2020-05-07 06:19 AM
> do you offer to volunteer to investigate this item deeper?
No, but I have lots of ideas and advice for others to try :)
2020-05-07 06:32 AM
That's fair.
JW