Well, as my other post has not resulted in any answers, here now is a "C" question.
https://forum.allaboutcircuits.com/threads/beaglebboneblack-mcp23017-code-no-longer-working.148883/
It has my Python code there.
So does anyone out there have "C" code to run on a BeagleBone Black, driving an MCP23017?
I have spent many hours trying to find example that I can understand, but to no avail.
It is looking like I will have to make an adapter so I can plug my board into a Dreaded Arduino to test it.
I think I can manage the Arduino version. It is a pity as I would have liked to get it going on the BBB.
This is so frustrating as I had it all working well until letting the magic Smoke out. Actually, there was no smoke, but you get the idea.
Here is the board I want to test.

I swapped the two 2 pin plugs to the right and popped the BBB

 

The code is very similar to the ds1307 RTC code... It would probably take 10mins or so to change it to suit..

I tend to use the SPI version, so I've never bothered.. When I get home tonight, I'll give it a bash..

 

The code is very similar to the ds1307 RTC code... It would probably take 10mins or so to change it to suit..

I tend to use the SPI version, so I've never bothered.. When I get home tonight, I'll give it a bash..

Thank you for your reply
It is probably a library problem and I just can't figure out how to drive them.
I was so pleased with myself getting the original Python one going that I actually emailed a couple of friends to tell them. Then I blew it up...
Oh, I have not managed yet to get the Arduino one running either. I should stick to "solder" as my programming language of choice!

FYI, the motor drive H bridge used on this board is the A4950
https://www.allegromicro.com/en/Pro...terface-ICs/Brush-DC-Motor-Drivers/A4950.aspx
I'm really impressed with it. A 40V 3.5A driver in a SMT 8 pin pack.
Well worth a look I reckon!

 

The C routines will be a lot lower level than object python... I will try to comment as best as possible..

 

I lied... It took almost 1/2 an hour... You'll need someone to change the registers as I use Pic's

mcp23.h and mcp23.c are attached..

Sorry!! I forgot to comment it.. I'll do it tonight!!

 

Thanks
I'll have a play a bit later.

EDIT: 4 hours later...
Hmm. No good.
I think libraries are one of my downfalls....
"xc.h: No such file or directory" Found one,
then "c_config.h: No such file or directory"
then "xc_funcs.h: No such file or directory"
then a lot more errors...
Really, I need a file with no includes.
I think I will give up. I don't know enough to fix this. Thanks for the try to help.