Pull-up documentation mismatch

[geby]

In Readme.md in the wiring section you have "note 2" about 1k resistor as pull-up on ReadData signal only.

However in shield schematics you have pull-up resistor on Index signal too, and both resistors are 10k for UNO, or 1k for Mega.

So, what is correct resistor value? Should not be "note 2" on Index signal too?

Thank you!

[dhansel]

Thanks for pointing this out. The correct resistor value is 1k, I have updated the schematic.

The 1k resistor on the Index signal is not really necessary, I just added it to the shield out of extra caution. The ArduinoFDC library activates the internal pull-up resistors in the Uno for both the ReadData and Index signal. However, those pull-ups are pretty weak and for a fast-changing signal like ReadData it may be too weak to pull it up quickly enough for the next pulse.

The Index signal is the only other input signal that also changes frequently, albeit not nearly as quickly as the ReadData signal. So I decided to put a pull-up resistor onto the shield just in case it ever became a problem. However, I have never had any issues without the Index pull-up resistor. For this signal the internal Arduino Uno pull-up is sufficient. You can populate the resistor or leave it out, it shouldn't make any difference.