Trouble with JTAG
2005-11-22 by Howard Amos
I am using a mega32 with my own PCB (no JTAG socket). Started using an ISP programmer (Avtiv8r from Meridian). In setting all the fuses I disabled JTAG (had no use for it)... How I have just bought an AVR JTAG ICE (from kanda.com) and want to debug using JTAG. My PORTC comes out to a 10 pin strip, so I make a cable to connect to the JTAG cable on the ICE. I turn on JTAGEN and OCDEN using the ISP programmer. Trouble is, PortC.2 (TCLK) is OUTPUTTING a '1'. The ICE wants to drive a '0'. As I understand things, when JTAG is enabled, TCLK should be an input to the AVR, so therefore I cannot have JTAG enabled. So I stop and restart my ISP programmer, and READ the fuses. JTAGEN and OCDEN are enabled (programmed), but TCLK is still an OUTPUT. Any ideas. Many thanks, Howard Amos