High-Voltage Programming requires the target voltage to be set to 5V. If you have any external hardware connected to STK503/STK500 that does not tolerate 5V, it must be disconnected before you High-Voltage program the AVR
STK500 | |
---|---|
VTARGET | Mounted |
AREF | Optional |
RESET | Mounted |
XTAL1 | Mounted |
OSCSEL | Mounted, pin 1 and 2 |
BSEL2 | Mounted |
PJUMP | Open |
STK503 | |
XTAL switch | Position near crystal socket |
TOSC switch | Not important |
After programming is completed, make sure you remove the cables between PROGCTRL, PORTD, PROGDATA and PORTB. Also remove the BSEL2 jumper.