Flash wear out during development | 68HC12

We are using the HCS12DP256 with Cosmic ZAP and P&E MultiLink cable. The symptom that we are seeing is that after several weeks of programming the flash (maybe 10 x/day), it starts to act flaky. For instance, it may take two attempts to fully erase the flash, etc. Our concern is that we are using a 12 MHz XTAL (instead of the more common 16 MHz). Is it possible that something in our tool chain is overstressing the flash by applying programming voltages/algorithms for too long a time? Any insight or similar experiences? 607-656-2597

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I should have added this excerpt from the "Block Users Guide for the Flash256": 4.1.1 Writing the FCLKDIV Register Prior to issuing any program or erase command, it is first necessary to write the FCLKDIV register to divide the oscillator down to within the 150kHz to 200kHz range. The program and erase timings are also a function of the bus clock, such that the FCLKDIV determination must take this information into account. ... WARNING Because of the impact of clock synchronization on the accuracy of the functional timings, programming or erasing the Flash cannot be performed if the bus clock runs at less than 1 MHz. Programming or erasing the Flash with an input clock < 150kHz should be avoided. Setting FCLKDIV to a value such that FCLK < 150kHz can destroy the Flash due to overstress. Setting FCLKDIV to a value such that (1/FCLK+Tbus) < 5ms can result in incomplete programming or erasure of the memory array cells. It is on the basis of these statements above that I have reservations about what we are doing. 607-656-2597 -----Original Message----- From: Kellogg Dave [mailto:] Sent: Friday, October 11, 2002 3:28 PM To: Subject: [68HC12] Flash wear out during development We are using the HCS12DP256 with Cosmic ZAP and P&E MultiLink cable. The symptom that we are seeing is that after several weeks of programming the flash (maybe 10 x/day), it starts to act flaky. For instance, it may take two attempts to fully erase the flash, etc. Our concern is that we are using a 12 MHz XTAL (instead of the more common 16 MHz). Is it possible that something in our tool chain is overstressing the flash by applying programming voltages/algorithms for too long a time? Any insight or similar experiences? 607-656-2597 -------------------------------------------------------- To unsubscribe from this group, send an email to: To learn more about Motorola Microcontrollers, please visit http://www.motorola.com/mcu

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Flash wear out during development - Kellogg Dave - Oct 11 14:28:00 2002

RE: Flash wear out during development - Kellogg Dave - Oct 11 14:43:00 2002