Filtering noise from a wire

[Demon]

Even if you have the fastest MCU to decode rotary encoder, the bottleneck is the I/O expander and will not be fast enough to follow users speedy fingers!

Ioannis

This is a signal from an EC11 rotary encoder.

5vdc with 10:1 probe
.1 volt / division
.2 ms / division




It takes about 2.5 time divisions to activate; so about 0.5ms.

MCP23017 I/O Expanders can run up to 1.7 MHz in I2C mode.
MCP23018 I/O Expanders can run up to 3.4 MHz in I2C mode.
MCP23S17 I/O Expanders can run up to 10 MHz in SPI mode.

I'm not keen on the new addressing mode on the MCP23018 version. I'm hoping the MCP23017 is fast enough at 1.7 MHz in I2C mode. At worse, I'll learn how to use the MCP23017 at 10 MHz in SPI mode.

(nope, haven't done any math to check if it's possible, mainly cause I have no clue how to do that properly )