From 3c446334e9ab2761af3c76855250183585b61aed Mon Sep 17 00:00:00 2001 From: tmk Date: Thu, 19 Jun 2014 21:12:04 -0700 Subject: [PATCH] Updated FAQ (markdown) --- FAQ.md | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/FAQ.md b/FAQ.md index 9bb74c7276..a411c7c6f1 100644 --- a/FAQ.md +++ b/FAQ.md @@ -178,4 +178,18 @@ Pressing any key during sleep should wake host. - http://arduino.cc/en/uploads/Main/arduino-leonardo-schematic_3b.pdf - http://arduino.cc/en/uploads/Main/arduino-micro-schematic.pdf -Arduino leonardo and micro have **ATMega32U4** and can be used for TMK, though Arduino bootloader may be a problem. \ No newline at end of file +Arduino leonardo and micro have **ATMega32U4** and can be used for TMK, though Arduino bootloader may be a problem. + + +## Using PF4-7 pins of USB AVR(ATMega32U* or AT90USB*)? +You need to set JTD bit of MCUCR yourself to use PF4-7 as GPIO. Those pins are configured to serve JTAG function by default. If you are using Teensy this isn't needed. Teensy is shipped with JTAGEN fuse bit unprogrammed to disable the function. + +See this code. +``` + // JTAG disable for PORT F. write JTD bit twice within four cycles. + MCUCR |= (1<