View Full Version : disabling jtag

03-03-2010, 06:02 PM
hi everyone
i want to disable jtag in my atmega32 so can someone tell me how to do it.i am using avr studio4 gcc , pony prog.
and also i want to know how to use thi header file
#include <avr\iom32.h>

03-03-2010, 08:51 PM
in order to disable jtag on atmega32, u have to make JTAGEN = 1 which means unprogrammed (not ticked). JTAGEN is a fuse bit. be careful while writing fuse bits because wrong fuse bits can make microcontroller locked. i suggest to use ponyprog for writting fusebits because the interface is very simple.
for fuse bits setting, u can use this site ---

i found it very helpful. also dont forget to refer the datasheet.

gud luck :)

03-05-2010, 05:39 PM
hey i checked the jtagen bit in pony prog , security and configurations bits but now when i try to write some program it says device missing .i have not touched any other bits so wat might be the problem ??
is the chip lost ?
the spien is greyed out is it normal ??
i heard that isp cannot be turned off by using isp so is the chip alright ?
cause i am worried about loosing the micro...

03-06-2010, 12:40 AM
by default jtagen is checked or ticked. to disable it, it has to be unchecked. therefore u may have changed a wrong bit.
if u have changed the clock options, it may or may not work and have to use the required crystal with it. before that properly check the connection and software setting.
high voltage programmer can be used for correcting fuse bits in a locked microcontroller.
spien is greyed out because u r using a isp programming method and cant disable it.

03-07-2010, 12:35 PM
Thanks for your help .the problem seems to be solved now....