STK500 User Guide Datasheet by Microchip Technology | Digi-Key Electronics
USB AVR Programmer -Part #1300 - Other Pololu products - Pololu Forum
STK500 Will not enter programming mode | AVR Freaks
STK500 User Guide Datasheet by Microchip Technology | Digi-Key Electronics
avrdude: stk500_recv(): programmer is not responding - Avrdude, stk500, Bootloader issues - Arduino Forum
Failed to enter programming mode. ispEnterProgMode: Error status received: Got 0xc0, expected 0x00 (Command has failed to execute on the tool) Unable to enter programming mode. | AVR Freaks