diff --git a/FAQ.md b/FAQ.md index 2935d6be..8df23af9 100644 --- a/FAQ.md +++ b/FAQ.md @@ -88,3 +88,22 @@ Use `1UL<<16` intead of `1<<16` in `read_cols()` in **matrix.h** when your colum In C `1` means one of **int** type which is **16bit** in case of AVR so you can't shift left more than 15. You will get unexpected zero when you say `1<<16`. You have to use **unsigned long** type with `1UL`. http://deskthority.net/workshop-f7/rebuilding-and-redesigning-a-classic-thinkpad-keyboard-t6181-60.html#p146279 + + + +## Pull-up Resistor +In some case converters needed to have pull-up resistors to work correctly. Place the resistor between VCC and signal line in parallel. + +``` +Keyboard Conveter + ,------. +5V------+------|VCC | + | | | + R | | + | | | +Signal--+------|PD0 | + | | +GND------------|GND | + `------' +R: 1K Ohm resistor +``` \ No newline at end of file