JTAG.h

Purpose: JTAG debug and boundary-scan interface.

Namespace: atmega2560::jtag.

TCK/TMS/TDO/TDI use PF4/PF5/PF6/PF7. Enabling JTAG assigns these pins to the JTAG interface and affects their GPIO use.

#include <atmega2560/JTAG.h>
 
namespace mcu = atmega2560;
 
static_assert(mcu::jtag::supported == 1, "ATmega2560 JTAG definition");

Signals

JTAG	Logical pin
TCK	PF4
TMS	PF5
TDO	PF6
TDI	PF7

The JTAGEN fuse setting and debugger configuration determine pin availability.

These are hardware definitions, not runtime register access or initialization.

Source: ATmega2560 datasheet (DS40002211A).