Battery backed 32k Ram

[janvb]

With 32k sram installed i no longer use my atom diskdrive at this moment.
For loading programs i use parallel port and an arduino uno.
But for this to work, i first got to load a machinecode program into the atom.
Do this now by cassette input. Wav file on windows PC. Gets a bit boring now to do it again and again.
To have this program non volatile in memory i have 2 options, ROM or since i have 32k Sram in a single chip a battery .

You can see the wires, red and black connected to the W24512 IC.

Did some test, and yes it works… but not always, had to connect a resistor to Vcc and CE to make it work proper.
At first had a regulated power supply connected to the chip. Was very curious how low i could drop the voltage.
Did go as low as 3V and then got an error and worce a randomised screen
I thought , "GLOEIENDE GLOEIENDE NONDEJU" what have i done now ?? (cursing in dutch).

But finaly found the oops, it didn't have anything to do with supply, but was an accidental coincidence.
To make a long story short, there is a chip beneath the RAM board, IC23, wich seemes to have bad contacts.
This explains also the weird graphics i had some times. (for those who have weird graphic things going on, check this ic).

All works fine now .

Gr.

Jan