i was looking about JTAG programming for ATMEGA32.
To be able to use the JTAG interface, the JTAGEN Fuse must be programmed. The device is
default shipped with the fuse programmed.
This mean that JTAG its already enabled by ATMEL. I checked it.
but that who i don't understand is:
In addition, the JTD bit in MCUCSR must be cleared.
Alternatively, if the JTD bit is set, the External Reset can be forced low.
if JTAGEN its programmed and JTD is set, then, there's will External Reset in my AVR. right?
Then, the JTD bit will be
cleared after two chip clocks, and the JTAG pins are available for programming.
JTD returns to zero after two chip clocks. which means that JTD it will always cleared when JTAGEN is programmed.
This provides a
means of using the JTAG pins as normal port pins in running mode while still allowing In-System
Programming via the JTAG interface.
finally JTAG pins are used as normal port and JTAG interface its available for programming... simultaneously?