8x8 matrix with 1 MCP23017 - Raspberry Pi Forums

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is possible setup 8x8 matrix using 1 16 io port expander via i2c? use left 8 ports columns , right 8 ports rows? i2c fast enough update 64 leds reliably?

thanks.

cole1717 wrote:is possible setup 8x8 matrix using 1 16 io port expander via i2c? use left 8 ports columns , right 8 ports rows? i2c fast enough update 64 leds reliably?
thanks.
fwiw, time ago attempted similar 2 x mcp23008's (equivalent 1 x mcp23017):
http://www.cpmspectrepi.webspace.virgin ... blepi.html
(never quite got around posting "working photo's though :( )
there spi versions of both chips if i2c proved "too slow". there's spi led display driver i.c. includes "hardware multiplexing" makes "life easier"!:
http://www.cpmspectrepi.webspace.virgin ... odule.html
(and, it's more conventional use 8-digit display driver:
http://www.cpmspectrepi.webspace.virgin ... odule.html )
trev.


raspberrypi



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