ISP on P89C51RD2BA

[Paul P.]

Hello.

I am new to the uC world. I have a P89C51RD2BA and I want to use the ISP facility. I have read the AN461_11 and the P89C51RA2_RB2_RC2_RD2_2 documents from philips and I am somehow confused. In the AN461_11 they enter in ISP mode by holding PSEN and Vpp low, while in the other document they only hold the Vpp high (+5 to +12). Am I mistaken somewhere? Which one can I use?

Thank you,
Paul.

[markus_13]

Hello Paul,

when you fullfill both conditions
> PSEN low
> Vpp high or 5..12V
and
>leave ALE/!PROG open

in that moment when reset is going down //falling edge//, it should work.

Really confusing for me was the description of P2.7...which was necessary to pull HIGH in the first generation (......H )of that device. But I think AN461 from 200-03-11 should be allright....regards markus

[Paul P.]

Thank you Markus.