4.1.2 Other Headers

In addition to the Xplained Pro Standard Extension Headers, ATmega256RFR2 Xplained Pro has additionally two headers with spare signals which offers access to the I/O of the microcontroller which are otherwise not easily available elsewhere or might be favorable to have collected together. All headers have a pitch of 2.54mm.

Table 4-6. SPARE ADC Signals Header
Pin on header	ATmega256RFR2 pin	Function	Shared functionality
1	-	VCC (3.3V)
2	PF4	ADC4⁽¹⁾	JTAG Interface, TCK
3	PF5	ADC5⁽¹⁾	JTAG Interface, TMS
4	PF6	ADC6⁽¹⁾	JTAG Interface, TDO
5	PF7	ADC7⁽¹⁾	JTAG Interface, TDI

Note:

These lines are connected to the JTAG interface, and ADC will not work properly while debugging or programming the kit.

Table 4-7. SPARE Signals Header 2
Pin on header	ATmega256RFR2 pin	Function	Shared functionality
1	AREF	Analog reference
2	TST	Test pin for RF test mode
3	RSTN	Reset	EDBG and RESET button
4	RSTON	Reset status
5	CLKI	Alternative main clock input
6		GND