[WP 34S] I finally bricked it :-(

[PANAMATIK]

(02-02-2015 08:19 PM)John Galt Wrote:  

(02-02-2015 07:57 PM)walter b Wrote:  I doubt it. Even you would not have been able to flash it 10 000 times.

It was not from lack of trying :-o

Does the erase action do anything at all, if flash memory has already been erased?

The reason for asking is that I did not flash it nearly as much as I erased it. I understand the flash (write) limit as you explain, but over the course of my initial experiments the number of erase cycles easily exceeded those by 10x. Still, I think those erase cycles (or attempts at erase cycles) was < 200 or so. The total number of actual, successful flash (programming) events was ten or fifteen. No more than that.

Erasing and programming flash memory is my daily work. The 10000 cycles are the number of guaranteed erase cycles by the datasheet of the manufacturer. You will have to flash the same chip for years to get over this limit. If you flash ten times a day you need three years. And the not guaranteed cycles can exceed the guaranteed by factor 3 up to 10. The programming cycles dont count. While developing my ACT I flashed the same chip about 50-100 times every day for debugging. There is no practical limit.

If programming is not longer possible it can have two reasons, the serial input/output or the whole chip is defective, or the boot loader firmware has overwritten itself or at least the interrupt vector table or the reset vector. This is the most common boot loader software mistake. There is a very short window when the reset vector will be written, about 10 ms, if the transmission is interrupted at that moment, the bootloader cannot start up the next time.

If you have JTAG tools and a complete binary file including the bootloader you could restore the chip. This is the engineers approach. The practical approach is to buy five other HP30b's, this is cheaper than the JTAG development system.

Bernhard