2.5 MISO

When Reset is applied to the target AVR microcontroller, the MISO pin is set up to be an input with no pull-up. Only after the “Programming Enable” command has been correctly transmitted to the target, the target AVR microcontroller will set its MISO pin to become an output. During this first time, the In-System programmer will apply its pull-up to keep the MISO line stable until it is driven by the target microcontroller.