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contiguous gpio

Question asked by Henry Sharp on Aug 28, 2017

First of all, please, excuse my newbness, I'm not familiar at all with the STM32 family and it is my first project with it.

 

For this project, I will use Waveshare core429i module (http://www.waveshare.com/core429i.htm ). The board has reserved pins for the 2MB SDram, the oscillators and for JTAG.

 

I will need for my project 1x16bit data + 1x8bit data gpio ports + 16bit LCD. I played (for a long time) with STCube, but I can't figure out how to get these two gpio ports at the same time as the other features. Each feature has its pins scattered on every single gpio block, I don't really understand why each feature is not grouped into a single gpio block. Anyway, after trying lots of combinations, I came to the conclusion it is not possible to have these 3 features + 2 gpio blocks at the same time on a 176 pin ic. :-/

 

I guess I could use the remaining pins scattered all over the place for my IOs, but then, I will have to read multiple registers, then put together the bits one by one to get my data at each read operation and break it into single bits and write into multiple registers for each write operation. Not really efficient and I'm not sure I will have time to do that between two io operations anyway...

 

Sooo, my question ;-) Did I miss something? is it really not possible to have 24bit of gpio on contiguous bits when using only 63 pins on a 176 pin chip???

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