32k RAM , #0000 #7FFF

[janvb]

Hello Acorn friends,

I know this has been done many times in the past, but just a short note of what i have done.

Had some W24M512AK 64 kbyte sram chips lying around.

Chipselect pin 22 is just connected to A15 of the 6502.
So if address line 15 is low, address #0000 to 7FFF can be addressed.
Connected CS2 and A15 from de ramchip to Vcc and OE to Vss.
The WE pin 29 is connected to pin10 from the 2114 chips (yellow cable).

After powering up the Atom shows ATOM > .
I can save and run a program.
Have to do some tests though if all works wel.

Jan

[janvb]

With the disatom rom fitted, i filled all the RAM with #FF (with NUKE command).
They where all correctly filled .
So got 32k RAM functional. for meself

[oss003]

Nice job ... works great without diskdrive because the diskcontroller is located at #0Axx. You can always relocate the diskcontroller of course...

Greetings
Kees

[roland]

Remarkable that this setup does not clash with the buffer IC4....

IIRC this bus driver is enabled for all addresses between #400 and #7FFF, excluding the lower memory area #2800-#3BFF. And it is enabled for the DOS ROM area #E000 - #EFFF.

[janvb]

Nice job ... works great without diskdrive because the diskcontroller is located at #0Axx. You can always relocate the diskcontroller of course...

Greetings
Kees

Indeed Kees.
Atom Disk Drive goes for a while in the storage cabin.
Intend to load programs through parallel port 6522, with arduino.
What's the benefit of this you ask .
Ehhhhhhh, there is no benefit at all.
I do this just for fun. Realy enjoy it all. Especial when it works the way i thought of it.

Gr.

Jan

[janvb]

Jan

[roland]

This screen shows that your Atom is screaming for more RAM .... you can easily add 2K extra
Consider replacing the video memory by a single 8K static ram, that might solve your screen issues, saves energy and adds more RAM. If you need some more information or some components then let me know!

[janvb]

Hi Roland,

Solved the screen issue, ic 23 had a bad contact.
32k ram is more then enough for me .
Added battery to it, so I have actual 32k eeprom, to store stuff.
Don't have to burn ROM's anymore.
Gr.

Jan

[roland]

32k ram is more then enough for me .

That's what I thought a few years ago but my Atom now has 512KB RAM. And I am working on a project that actually is going to use a lot of this memory.

I can really recommend Hoglet's noise killer video ram board. It gives a nice and quiet screen when working in video RAM. It's a simple, small board that is easy to put together, so if you're interested just have a look at the Atom Video to HDMI adapter topic.