Flash Magic Forum

In-System Programming Support => P89C51Rx+/P89C51Rx2/P89C66x/P89C6xX2/P89V66x => Topic started by: kssathis on June 25, 2007, 10:53:32 pm

Title: Communication Problems With P89C61X2BN
Post by: kssathis on June 25, 2007, 10:53:32 pm
Hi,

I used the circuit suggested by Flash Magic Software.
According to this connection , I communicated( i.e Programmed the P89c61x2bn) once, afterthat i switched off the circuit.

Now I tried to communicate it , I got the "Unable to communicate" Error display.

Pls. kindly suggess on this.

with thanks,
Sathish
Title: Re: Communication Problems With P89C61X2BN
Post by: Andy Ayre on June 26, 2007, 09:11:46 am
After reviewing your debug file:

The device is not entering ISP mode. Can you please use a scope to check RST and PSEN. PSEN should be low at the falling edge of RST. /EA should be at +5V and ALE should be floating or high.

Andy
Title: Re: Communication Problems With P89C61X2BN
Post by: kssathis on June 29, 2007, 12:43:34 am
After reviewing your debug file:

The device is not entering ISP mode. Can you please use a scope to check RST and PSEN. PSEN should be low at the falling edge of RST. /EA should be at +5V and ALE should be floating or high.

Andy

Hi I watched that PSEN and RST pins with use of Oscilloscope. Both are fine, The Microcontroller IC is also changed. I also sent the circuit diagram what i used for this from mail ID "kssathis@gmail.com". Pls kindly suggess me, what I do to make a device to enter the ISP mode.

with thanks,
S.Sathishkumar

Title: Re: Communication Problems With P89C61X2BN
Post by: Andy Ayre on June 29, 2007, 09:05:04 am
Did you check ALE and /EA?

Andy