P89C51RD2B

[Daniel Ramognino]

Hi all

Using FlahMagic I can program and reprogram the flash without problem when I use it in 12 clock mode.
When I set the FX2 in Flash Magic I can only program the first time. Then I cannot do more ISP.

I am using the circuit according AN 461 page 12, but with Vpp connect to a capacitor an resitance as state in the errata.

Can anyone suggest what else can I do ?

[Andy Ayre]

Are you able to communicate with the device at any baud rate?
Are you using the high speed communications option? If so does turning it off help?
Are you able to communicate with the device at all or is just programming a problem?

[Daniel Ramognino]

Andy thanks for your reply.

Here is the problem:

1. I insert a new P89C51RD2BN for the first time in a ZIF socket in a circuit according page 12 of AN461.
2.I can communicate without problem.
3.Then I program it but without the FX2 option set.
4.I put the part in my application board and everything is fine.
5. Then again in the ZIF socket  and I can reprogram the part again without problem.

But if  in point 3 if I set the option FX2 and program it, the application will run perfect in the application board at double speed.

But when I tried to reprogram this part again I am not able to communicate at any speed. It seems that it cannot enter ISP mode.

The application program is the same in both cases.

I hope this could let you understand the problem I am facing.

Thank you.
Daniel