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Charlieplexing with MCP23017
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Charlieplexing with MCP23017

by Tinaja on Fri Jun 14, 2019 7:26 pm

Is there a way to set an IO pin on a 23017 to HIZ after it has been set to output so I can use a single pin to drive 2 leds? Does just switching the port to input do this?

This feels like a stupid question after typing it...
Tinaja
 
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Re: Charlieplexing with MCP23017

by XRAD on Sat Jun 15, 2019 3:17 pm

Last time I used one of these, IIRC input pullups available only, and 20ma output max. You could add a 2n3904 with 500+ohm base resistor for 100+ma on the MCP output pin....

XRAD
 
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