An ICSP programmer needs to hold reset low during programming. If you only have 3 pins over better use a normal (serial) bootloader. You will need Rx, Tx, Reset, plus power and Gnd.
An ICSP programmer needs to hold reset low during programming. If you only have 3 pins over better use a normal (serial) bootloader. You will need Rx, Tx, Reset, plus power and Gnd.