STM32 noob needs help with STM32H523V project

[memotronics]

Hi all,

I'm new to the STM32, I'm more of an 8-bit AVR guy and now I've grown up and want to play with the big boys.

My project requires a lot of I/O, so I landed on the STM32H523VE. I'm developing in the Arduino IDE, and I think I've managed to get the IDE set up, more or less. I'm not using any pre-made boards. For now, I'm talking directly to the MCU.

I need some help getting a better understanding of how to deal with certain I/O requirements, because the AVRs that I'm used to don't have support for those on the MCU, instead I'm used to having external ICs manage those, connected via SPI, I2C or parallel.

Here's what I need to talk to:

- SD-Card
- USB Keyboard (so STM32 acts as USB Host)

and my questions are:

- For SD, should I just use SPI or should I use the built-into-the-MCU SD-card support ?
- For the built-in USB, how would I go about it (library-wise and code-wise) ?

Also, unrelated to I/O: When running at full speed (250 MHz), is the interrupt overhead for a GPIO-initiated interrupt known? By that, I mean: How much time passes between the time that there's a signal transition on the pin until my interrupt-attached code starts executing? And when my interrupt-attached code finishes, how much time-overhead is there on the tail end?

Thanks !

JE

[ozcar]

...

Also, unrelated to I/O: When running at full speed (250 MHz), is the interrupt overhead for a GPIO-initiated interrupt known? By that, I mean: How much time passes between the time that there's a signal transition on the pin until my interrupt-attached code starts executing? And when my interrupt-attached code finishes, how much time-overhead is there on the tail end?

Thanks !

JE

There is probably a fair bit of overhead in the Stm32duino and HAL code.

If you have a DSO you could toggle a spare GPIO in the interrupt routine. I have also done what I call the "out to lunch test", where I also get the mainline code to spin doing nothing other than flip another GPIO. EG as at viewtopic.php?p=2562&sid=c6ea9100e61396 ... e11a#p2562 .

I don't have a H523 to try that on though. I do have a couple of H503 boards but have not done something like that on one of those.