Scorpio and 23017 chip... trouble with I2C

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GerryFP1
 
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Scorpio and 23017 chip... trouble with I2C

Post by GerryFP1 »

Hi All
I'm having fun with a Scorpio with 288 Neopixels using Arduino IDE ( 2.1).
For background visualise a chess board, each cell having 4 Neopixels and a reed switch, all bordered by a further 32 neopixels. In fact it's all spilt into 4 identical PCBs.

The next stage is the inclusion of 4 MCP23017 chips (for the reeds) but I'm having ( understanding ?) issues getting Ic2 to work.. at first with just one 23017 chip. Looking at the SCAN_IC2 example it doesn't seem to handle Scorpio as a board. Additionally the very flexibility of pin usage for Scorpio I2C confuses me. Anyone out there got any examples or hints for me PLEASE ? Thanks in advance.. Gerry

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Re: Scorpio and 23017 chip... trouble with I2C

Post by adafruit_support_carter »

Are you using bare MCP23017 chips? If so, are you adding pull up resistors on the I2C lines?

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GerryFP1
 
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Re: Scorpio and 23017 chip... trouble with I2C

Post by GerryFP1 »

Hi. Yes (Bare chips) and no (resistors). I assumed ( perhaps wrongly) not needed for the Scorpio board. good hint . I'll try. What value ?

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Re: Scorpio and 23017 chip... trouble with I2C

Post by adafruit_support_carter »

Anything in the 2k to 10k range should be fine. 10k is a good generic starting value.
https://learn.adafruit.com/working-with ... -resistors

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