Hello Duc,
Am 24.06.22 um 16:28 schrieb Duc Doan:
Hello Christian,
On Thu, 2022-06-23 at 18:30 +0200, o...@c-mauderer.de wrote:
Another tricky part can be how to handle pins or pin groups. At the
moment I just used an "unsigned" for a single pin. That wouldn't be
able
to handle a pin group. Maybe a pin group needs it's own type or some
kind of extensible type. For the usual controller with <= 32 bit a
mask
in a uint32_t would be great. For other controllers maybe a longer
mask
is necessary. That's a bit tricky.
Thank you for the pseudocode, I think your method is better than mine.
I am currently rewriting the code. However, I am not clear about pin
groups: Is a "pin group" same as a "port"? Or does a group mean pins
from that group can come from different ports/GPIO controllers?
It's not unlikely that you want to change multiple pins on one
controller at the same time. That's what I meant with "pin groups". On a
controller level it would be (for most controllers):
- Read current value from output register into a temporary variable.
- Change the pins in the group to the new value in that temporary variable.
- Write back the new value to the output register.
Also, I am thinking that maybe I can create an opaque type for pin mask
that BSPs will implement, instead of a specific type like
uint32_t. That type could be used as a long mask or just a pin number,
depending on the BSP.
Be careful with everything that depends on the BSP. Again: Please think
about an i2c GPIO expander. That chip can be used on different BSPs. It
can be even an independent driver that can be used by a user on demand
on any BSP that supports i2c.
Best regards
Christian
Best,
Duc Doan
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