Driving an LED matrix + reading an SD card

viitana_2
Posts: 1
Joined: Mon Apr 20, 2020 8:46 pm

Driving an LED matrix + reading an SD card

Postby viitana_2 » Mon Apr 20, 2020 9:08 pm

Hey all, sorry if this is not the correct subforum for this, I had a bit of trouble identifying where I should ask.

I was planning on using an esp32 to drive a 64x64 LED matrix panel using this PxMatrix driver. The idea is to display a simple animation/video which I would probably store in bitmaps.

I wanted the setup to be standalone so as I understood it my options would be to either store the video in the very limited flash memory that is also used the code itself etc. or read it off an SD card. Ideally I would like to use an SD card. However, looking at the documentation for driving the pixel matrix, I would need to reserve pins 2, 5, 13, 14, 15, 18, 19, 22 and 23 for it. Looking at the SD card libraries I could find, e.g. this default one, some of the pins would overlap.

So the question is, is a setup possible where I could use an esp32 to drive the pixel matrix as well as read data off of an SD card? Sorry if I'm asking anything obvious, I'm not that familiar with programming these boards and I only have some previous experience using an Arduino MKR1000 :D

A setup somewhat similar to what I'm trying to achieve can be seen here.

PeterR
Posts: 621
Joined: Mon Jun 04, 2018 2:47 pm

Re: Driving an LED matrix + reading an SD card

Postby PeterR » Tue Apr 21, 2020 12:17 pm

Yes.
You need to tell your driver to use different pins. If the pin is not native SPI then your maximum clock rate will be reduced.
to either store the video in the very limited flash memory
You have 4MB. You could have up to 16MB last time I checked.
Assuming RGB without intensity then that is 3 bits per pixel = 1.5KB per frame. 30KB/s? So 30 seconds per MB? Lets say you have 3MB free so 1.5 minutes? How long do you want?
& I also believe that IDF CAN should be fixed.

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