The Prog Ctrl and Prog Data headers are used for High-Voltage programming of the target Atmel AVR device. The placement of the headers is shown in the figure above. During parallel High-Voltage programming, the Prog Ctrl signals are routed to PORTD of the target device. The Prog Data signals are routed to PORTB. See High Voltage Programming for complete description of High-Voltage programming. The pinouts of the Prog Ctrl and Prog Data headers are shown in the figure below. For more information about High-Voltage programming of AVR devices, see the programming section of each AVR datasheet.
ProgCtrl and Data connector are connected directly to the master MCU without level converters. This means that these signals are always 5V logic.
The Prog Ctrl signals are normally used for the control signals when parallel High-Voltage programming an AVR device. The Prog Data signals are used for the data bus when parallel High-Voltage programming an AVR device. During ISP programming DATA5 is as MOSI, DATA6 is used as MISO and DATA7 is used for SCK.
All Prog Ctrl and Prog Data signals are based on 5V CMOS logic. No voltage conversion to adapt to VTG is done on these signals.