Darryl,

     I have been using a UV eraseable PIC14000 in my project. At first it
     took only about 5 minutes to erase the chip.  After about 5 erasures
     this time had increased to 10 minutes. Finally at about 20
     erase/program cycles the chip FAILED to erase. I have _never_ had this
     problem with other EPROM devices.

     Maybe the guys at MicroChip would care to comment?

     Joe_Dowlen@egginc.com




______________________________ Reply Separator _________________________________
Subject: UV Pic problem
Author:  pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU> at SMTP
Date:    12/3/96 10:03 AM


Dear All

I am currently developing a PIC16C63 application. I am using a UV erasable
part in the development phase. My problem is that my device will no longer
erase after only 3 erase cycles. All the data appears to be 0.

- Could this be a result of leaving the device to 'cook' for too long
  in the eraser ?

- Should I expect this from microchip devices ?

As these devices are costing 25 pounds each, any ideas very welcome.

I do have one other problem with this device. I am using the UART and am unable
to clear the receive interrupt. I thought that reading the received data would
clear the interrupt flag.

In a test program I have the PIC connected to a terminal and on receiving a
character from it it is echoed back. The receive works from an interrupt.
After sending only one character it is continually echoed back to the
terminal. I therefore assume that the interrupt is not getting cleared.

Again any pointers gratefully taken.

Thanks

- Darryl