ISP via PC Parallel (printer) port

Originally on MembersPage/MattiasSandgren/NickesBMW/AvrBootCode

(thanks Mattias).

AVR pin commandISP header #Parallel port pinNotes
AVR /RESET57Yellow
AVR SCK (clock input)38Black
AVR PDI (RXD) (instruction in)49Red
AVR PDO (TXD) (data out)110Orange
Signal Ground618Brown
* MOSI and MISO are not used.

Correct pins from the schematics AVR pin 2 = RXD/PDI -> ISP header Pin4, AVR Pin3 = TXD/PDO -> ISP header pin 1

See signal functions vs header pins [bottom: \"VEMS V3 ISP pinout\"] (also called "ISPI")

The avrdude bsd pinout is compatible with the alf pinout (so -c alf should work just as well). The alf code also sets some status (ready, error, verification, complete ...) LEDs that can be useful for fancy geeks (although the same info is also on avrdude screen, and some in return value).

This is what it looked like:

avr_isp_cable_attached.jpg avr_isp_cable_ends.jpg

330 Ohm recommended on all 4 signal lines (or sg. between 270..348 Ohm for protection)