...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
| Table of Contents |
|---|
Introduction
Some games that run in RAM, particularly when in combination with OZ v4.6 and later - running in slot 1, fails to run on the 512K/512K Flash/RAM Card due to a timing error which is introduced by the decode chip CD74HCT139. This is one of the fastest decode chips but it is too slow for our purposes.
...
| Inputs Enable Select | Outputs | |||
|---|---|---|---|---|
| /E /CE | A0 A19 | /Y1 /CE1 FLASH | /Y0 /CE0 RAM | |
| 00 | 0 | 0 | 1 | 0 |
| 01 | 0 | 1 | 0 | 1 |
| 02 | 1 | 0 | 1 | 1 |
| 03 | 1 | 1 | 1 | 1 |
00
01
02
03
They both agree.
Circuit Diagram
Timings
Trawling through the datasheets for NAND gates found the following:-
...
Extra components required
Component | Manufacturer Part No | Order Code | Price | Min Qty |
|---|---|---|---|---|
N95BT | Maplin | 4.09 | 1 | |
YA29G | Maplin | 1.79 | 1 | |
MFR3 2K2 FC | 1565301 | £0.085 | 10 |