I've bought a used NS 8 GPS two months ago. It had an upgradable MC, which could be upgraded to MC4.06 with a serial cable.
But the Hand control had V1.2 on it, which thanks to the hint of the OP, has been upgraded to V2.2.
I have used a GALEP IV programmer and a PLCC to DIP adapter.
The PCB was marked with the label "NXW210 REV.B 2001"
The PCB of my hand controller has a PIC16C756A microcontroller and two AT49F040 flash memory chips (for a total of 512kx16 memory)
But now, with the GPS rollover problem I have investigated a little more the firmware versions and I noticed that the NXS98.22 (which is a v4 firmware) the same size as the V2.2 firmware is (512kx16). Furthermore it is combatible with the 16C756A processor of my PCB.
So I flashed the 49F040 flash memory chips of my hc with the NXS98.22 binary file (after splitting it in high and low bytes of course). After powering up, the HC booted normally and the 98.22 firmware (V4) is running on my old HC. So far everything works fine.
I've tried also the serial cable upgrade, the HC upgrade program finds the HC, but when a programming procedure starts, the whole flash memory is being erased, including the boot loader, so the in-circuit programming cannot be continued and the memory chips have to be programmed with an external programmer again.
For the 49F040 there is a boot-block protection option, which prevents the boot-block from being deleted-altered. I've tried this also, but with no success. Apparently the V4 HC uses another flash memory chip like 29C040 which allows a single block erase...??
My questions are:
has anybody opened his V4 HC and knows what memory chips are installed?
Also, does anybody have the schematic of the V4 HC, to confirm that the two controllers are compatible?
Or could somebody take a photograph of the pcb of his V4 Hc.
It would be helpfull for a lot of people, as many have an old hc, which is (was) considered as non-upgradeable to V4.
Edited by fmav, 22 June 2019 - 08:50 AM.