How to use adafruit matrix without a backpack

Firmware
1

Hi there

I wonder can I use an adafuit 8x8 matrix without a backpack. If it is doable, how can I wire it to the photon correctly and is there a library for it?

Thanks,
Chunxu

2

Hey @huan1445, can you provide a link to the matrix you’re looking at? What are it’s voltage requirements?

3

@huan1445, connecting the 8x8 matrix will require 16 GPIO lines which the Photon doesn’t have. You could use a high power shift register to drive the anodes (as suggested by Adafruit) and then drive the cathodes using 8 GPIO lines. In total, you would need 10 GPIO lines to drive this arrangement. Another, better approach, is to use an MCP7219 via I2C to drive the matrix. This is what the backpack does.

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