| What is it? | ||
| This is a PCB for an expansion of 8k Static Ram | ||
| Why did you make it? | ||
| I wanted to be able to use expansion RAM in some programs. | ||
| In the photo below left the red link selects which 32k block this 8k will reside in. | ||
| The blue link selects which 8k block this 8k will reside in. | ||
| The top 4 links are active.From the top they select:- | ||
| X000-X7FF. | ||
| X800-XFFF. | ||
| Y000-Y7FF. | ||
| Y800-YFFF. | ||
| This PCB allows me to place an 8K RAM block in one of 8 different locations in the SBC memory Map. | ||
| What makes it special? | ||
|
It is a very simple and useable design. |
||
| Bill of Materials:- | ||
| 1 x 74LS245 | ||
| 1 x 74LS139 | ||
| 1 x 74LS00 | ||
| 1 x Toshiba TC5565 or equivalent 8K x 8 Sram. | ||
| 1 x 36 way right angled header strip | ||
| 1 x 2 x 8 header strip.( only use 2 x 4 on this board). | ||
| 1 x 3 header strip. | ||
| 2 x Links. | ||
|
|
|
|
||
|
||
| (c) 2021,2022,2023 Paul Bartlett | ||