MCP Limit switch pullups/downs

Post by **Basicmicro Support** » Mon Jul 12, 2021 1:29 pm

When using a pullup on a MCP I/O pin(or pull down) please keep in mind the internal voltage dividers on each pin. They are 1200ohm series and 2200ohm parallel. This means each I/O has an impedence of 1200ohm and any pullup will need to be stronger than 2200ohm and low enough to pull up above 2v. A 1k resistor is recommended for all pullups.

For pulldowns you can rely on the internal 2200ohm without using any external pulldowns.