battery back-up chip ram

[tomthul]

I made this just to see if it would work. It is battery backed chip mem.
A recoverable ram disk (RAD can be created to boot the computer. The contents of the ram survives a power off....RAD: takes about 60k of chip
I can boot my A500 without a floppy disk.

tom

 

[Zetr0]

Tom this is fantastic!

I do hope you manufacture these little pretty's =)

 

[mjnurney]

Ohh very interesting . I have always wondered if the chip ram could be battery powered on the mobo before...

Mike.

 

[SpeedGeek]

This might work for the second 512K of Chipmem but for the first 512K you would need to supply power to the 28 MHz oscillator, Fat Agnus and the DRAM as well. So plan on getting a bigger battery and some hacks to separate their +5V supply from the rest of the A500 logic as well.

But maybe some auto-config fastmem/SRAM could simplify things a bit?

 

[tomthul]

battery backed chip ram

battery backed chip ram

Hello, the circuit uses SRAM. the on board DRAM is disabled.

tom

 

[NMI]

That's brilliant!

Do I understand you correctly that you have disabled all onboard chip ram and replaced it with a 1MB (or 2MB if it is a plus) battery backed up expansion SRAM?

 

[Kitman]

Hi,

This looks to be a great piece of kit.
I would be interested for sure.

Well done (again) Tomthul.

K6

 

[bdb]

"It's not life as we know it or understand it." "Fascinating, Pure energy. Pure thought."

 

[NMI]

How about adding a Gary-adapter and bump the total amount of sram to say 4MB?
Would make a really interesting addon for the a500!