search

OlegMishin / A500_8MB_ide2

8MB FastRAM and BSC-AT-Bus IDE controller for Amiga 500
GNU General Public License v3.0
17 stars 0 forks source link

Where's my RAM? #2

Open pazuzu72 opened 10 months ago

pazuzu72 commented 10 months ago

Really Congratulations!! Super interesting project. I have everything to do it but I really don't know where to get the necessary 5v RAM. All the 72 pin modules I see around don't have that type of ram. Any tips?

OlegMishin commented 10 months ago

Hi, Thanks for your comment. It is in deed difficult to find the RAM. I managed to buy them on eBay. Sometimes the right SIMMs pop-up. You need to search for 16MB(2 chips) or 32MB(4 chips) SIMM modules. Some time ago I saw KM416C4104BS at some Chinese suppliers(Kynix or Utsource), but never tried to buy there. Could find SIMM modules.

pazuzu72 commented 10 months ago

I own a pair of ATF1508AS-10AU100, they should be fine I assume.

OlegMishin commented 10 months ago

Yes, this one is ok.

CCKMik commented 7 months ago

It is in deed difficult to find the RAM.

it would be good to have an optional voltage regulator so that 3.3v ram can be connected

OlegMishin commented 7 months ago

Hi @CCKMik, I would like to avoid a mixed voltage design as an absolute maximum rating for 3.3V RAMs is 4.6V at IO pins and the RAM is driven by 5V logic. It is a bad practice to exceed component's requirements. Moving to complete 3.3V design requires level translation buffers, which takes pcb space and makes layout more complicated.

I have no plan for further updates.