ISP problems

[Tapan]

hi!!
I am using the ISP feature for the first time. But it is not working.
I am facing the same problems what Mr Sunil Patil had faced.
I haven't used hyperterminal. But instead I have written a simple program in C to transmit 'U' and wait for the response from Microcontroller.
But that doesnt work. My com port is fine and I have tested it.
I have used the same circuit as described in ISP application note.
One thing i noticed which i feel is odd that when I see the voltage on /PSEN pin on Oscillscope I find that even though I have pulled down the /PSEN pin through 2K resistor it still shows voltage level of 5V.
Has this anything to do with the problem or it is normal??
I have not programmed it using parallel programmer. But I would like to check the BOOT VECTOR. But i dont know how to check it and if it is changed how should i modify it to FCh again
Regards------
Tapan Vinchhi.

[Andy Ayre]

If /PSEN still is high enough to be regarded as a logic 1 then that is
probably your problem. Does it show a voltage of 5V on /PSEN while you are
holding the device in Reset?

You can check and change the boot vector with Flash Magic, assuming you
can connect. Choose Status Byte and Boot Vector... from the ISP menu. The
current settings will be displayed.

Please only reply to one thread.

[Tapan]

Hi Andy!!
           Thanks for your immediate reply.
            My problem is sorted out.
            In my case there was a problem in serial cable connector at PC end.
            The following   pins need to be shorted in case of DB9 connector which I did'nt do.
            1-4-6 pins need to be shorted to each other and 7-8-9 pins need to be shorted to each other.
            I was not aware of this. But I found it on net.
            I immediately applied it and my ISP started working.
            Its really gr8!!!I really enjoyed it!!!
            Thanks.
             Regards-------
             Tapan.

[m s kattan]

i am using p89c664 controllers and i have problems of loosing the boot vector address ,is there is any way i can re wright the boot victor using
flash magic or build a simple circuit to do so thank you

[erikm]

"i am using p89c664 controllers and i have problems of loosing the boot vector address ,is there is any way i can re wright the boot victor using flash magic or build a simple circuit to do so"

No, but if you install NoTouch the first time you program the chip, it does not matter that you lose the vector.

ANYHOW, as usual, you did not install it at the start and it can not be installed once you have lost the vector.

You need buy or borrow a parallel programmer to restore the boot vector.

Erik