programmer 89c2051
Yes you can use the PC 5v and 12v, obvious through a switch. You can't plug the
micro in socket with power supply already applied.
To be honest I didn't tried the mentioned programmer:
http://www.geocities.com/dinceraydin/8051/index.html
but I build up with success the:
**broken link removed**
you can see the original developed by Herny Arndt, DL2TM here:
What it's weird with the
http://www.geocities.com/dinceraydin/8051/index.html is
that wouldn't be able to verify the micro after programming. My private opinion! Just because during verify the RST pin must be hold at "H" level which is +5v. You can see from the schematics that the RST pin goes toward ground when Q1 is biased and toward +12v when locked (during programming). Nevertheless, can you be so sure that after power supply is applied to the circuit, the parallel pin 14 is at high level ?.
Otherwise you must check with a DVM before fitting the microcontroller, just to avoid damage it.
What it will happen if your parallel port wouldn't provide bidirectional data bus features ?
Inside AT89C2051 data sheet
http://www.atmel.com/dyn/resources/prod_documents/DOC0368.PDF it's clearly stated (pag 6):
To verify the programmed data, lower RST from 12V to
logic “H” level and set pins P3.3 to P3.7 to the appropiate
levels. Output data can be read at the port P1 pins.
You can see a good design at:
http://www.qsl.net/dl2tm/atprog/atprog.htm
Look at the circuit Q1, D2, Q2, D1, R1 around the RST pin and you can figure out why I mentioned all these things above.
Regards,
silvio