Problem with programming P89C668

Started by eagle, September 15, 2006, 12:27:51 AM

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While i was programming the uC (ISP), I canceled the transmision. From this moment the uC don't go in the programming mode, and it executes in all moment, in program mode and run mode.

Somebody know the solution?, because in this moment i cannot program the device.


Andy Ayre

When you canceled the operation did you click on Cancel in FM or did you remove the power to the device or reset it?

Possibility 1:

If you removed power or reset the device and you did it at just the wrong moment then the boot vector might be corrupted. Only a parallel programmer can tell you for sure.

Possibility 2:

If this is your first time programming this device then you might not have the ISP entry method working properly. Devices come from the factory with the status bit set, so they reset into ISP mode. After programming FM clears the status bit. To get the device back into ISP mode you need to meet the conditions described in the datasheet. For example are you pulling P2.6 AND P.27 high at reset?

Embedded Systems Academy, Inc.
support at esacademy dot com



All conditions for ISP mode are correct, because i have programmed the device more times.

I canceled the programming when i clicked "Cancel" in FM. And now, with the good condicions for ISP mode, the uc don't enter in this state.

How do i do that the boot vector are correct?


Andy Ayre

That is odd. When you click on Cancel in FM it waits for the current operation to complete before stopping. Care has been made to ensure that the boot vector isn't corrupted, and this has been tried and tested for a long time now for the 89C66x devices.

Why did you chose to cancel the operation? Did it take longer than you had seen in the past?

The only way to see the boot vector is to use a parallel programmer.

Embedded Systems Academy, Inc.
support at esacademy dot com


Thanks, but I have already solved the problem. I have changed the uC, because i haven't the parallel programmer

Muchas Gracias.