Ram

The Need for RAM Testing Before running any critical code, especially on vintage or newly built Z80 hardware, you must verify that the Random Access Memory (RAM) is working correctly. Faulty RAM chips can lead to unpredictable crashes and data corruption. Goal: To ensure every memory cell can reliably store both a logic ‘0’ and a logic ‘1’. The Simplest Test: The Fill Test The fastest, simplest test is to fill the entire memory block with a single value (e.g., 00H or FFH) and then read it back to verify. However, this test is weak because a faulty address line might cause two memory locations to point to the same physical chip, and this test wouldn’t catch it. ...