Vers un upgrade des TI-82Stats.fr/76.fr (1ère partie)

[critor]

I wrote a ti 83+ dump from nitroroms.com, ti83+ v 1.12 19xx and no joy. My calculator is dead. I will try tomorrow to see the signals with a scope. I am very disappointed.

Apparently, your full 512K dump (got it privately) contains no Boot Code.
The last 256K are just filled with 0xFF bytes.

So there might be something on the board which tells the ASIC to directly run the code at the start of the ROM, instead of looking for a Boot Code at the end of the ROM.

Your calculator doesn't turn on ?
You might try the usual 83+ key combos :

• remove a battery, and hold while putting it back
• remove a battery, hold while putting it back, keep on holding and press

[sorin lipsa]

It is normal that the last half of memory to be FF since the last address is held at ground. There is no way that the mcu access that zone. I left my shop but not after try to see some signals on the scope and I noticed that I get no signal on A17, and even that A17 is held high. I will make tomorrow more tests

[critor]

It is normal that the last half of memory to be FF since the last address is held at ground. There is no way that the mcu access that zone.

Ah.

Then it doesn't prove anything and you need to unground the A15 pin :

[sorin lipsa]

I already done this, but I mean in original configuration it was no point to have something in the last half of the memory, since there is no way to access it. Now I write all the 512k of flash and for running correctly it need that the asic access A17 of flash but as I see on my scope that pin remains inactive.