# Encoders on MCP23017

**URL:** <https://discourse.zynthian.org/t/encoders-on-mcp23017/758>\
**Category:** Hardware\
**Created:** [June 6, 2017, 1:26am UTC](https://discourse.zynthian.org/t/encoders-on-mcp23017/758 "2017-06-06T01:26:04Z")\
**Posts on this page:** 1\
**Showing post:** 13

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**Author:** ![beckdac](https://discourse.zynthian.org/user_avatar/discourse.zynthian.org/beckdac/32/519_2.png) [@beckdac](https://discourse.zynthian.org/u/beckdac)\
**Post date:** [June 14, 2017, 12:25am UTC](https://discourse.zynthian.org/t/encoders-on-mcp23017/758/13 "2017-06-14T00:25:24Z")

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Another quick note. I included 4.7k pullups in my original prototype and it works fine. However, the Raspberry Pi 3 has 1.8k pullups on those lines so in practice on my prototype the final pullup resistance is 1.3k which is above the minimum for fast mode so there is no problem with the rise time. When I build another, I will leave off the external pullups. I have removed them from the schematic.

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