P89V51RD2 not detected all the time by FlashMagic

[gmisslin]

It seems that Flash Magic is not able to detect the 89V51RD2 after a reset initiated by clean reset pulse, the message "unable to connect at the specified baud rate" appears 60% of trials.

I am using max232 and rx/tx signals applied on the port COM.

The problem is not reduced even when port com speed is reduced.

There is no difference between using a regular port com versus a "usb to com" adapter.

The problem exists since a long time : it seems not to be design dependant and chip date code dependant.

Can someone of Flash Academy explains us how to improve that poor results ?

I noticed that this problem occurs whith other chips and Flash Magic and I wonder if it is really a bug or a manner introduced by Flash Academy to avoid using Flash Magic in production.

[Andy Ayre]

I'm not sure who Flash Academy is, but I doubt they want to avoid using Flash Magic in production.

With the 89V51Rx2 and 89LV51Rx2 devices the device must receive a 'U' on RxD within the watchdog timeout period after reset to enter ISP mode. What Flash Magic does is sends out Us as fast as possible and tells you to reset the device.

As far as we can see, this is the only feasible solution.

The watchdog timeout is the maximum timeout, however it is dependant on the crystal frequency. Therefore the faster the crystal the shorter the time to receive a 'U'. At 11.0592MHz the timeout is 400ms.

[Jan Waclawek]

What is your crystal/oscillator value and which baudrates did you try? What is the serial cable length? Can you also please describe the programming procedure you use?

Jan Waclawek