DRAM Tester for MZ-80 K/A and MZ-1200

Bugfix.

Fix an embarrassing bug in the test #4 (March-C): I just forgot to update the results visually so the test was always displayed successful even when the test fails (due to a DRAM chip removal). Hopefully, the previous tests detected the DRAM failure.

DRAM Tester for MZ-80 K/A and MZ-1200

• 8255 is now initialized properly.
• garbage display at power-up remains visible during 10s to witness CGROM is good visually.
• then video is set off to test VRAM between $D000 and $D7FF with pattern $55/$AA.
• if VRAM test is failure, a repetitive beep is issued and led toggles green to red and vice-versa.
• if VRAM test is successful, then it is okay to use VRAM as stack and draw intro.
• intro offers to start all DRAM tests by pressing [SPACE]
• there are 4 tests: 1) pattern $00/$FF R/W, 2) pattern $0F/$F0 R/W, 3) pattern $55/$AA R/W, 4) March-C.

DRAM Tester for MZ-80 K/A and MZ-1200

Bugfix and new test addition:

• Normally we have 3 rows of 16KB to test but ROW II was scanning 20KB and so can report not the right chip failure . It is now fixed to the expected 16KB.

• A second test called March-C is added to allow setting/clearing bits instead of bytes. It is a far slower test for that reason.

To leave a test, you must press and hold the SPACE bar until you get the next test introduction screen (with that pacman chewing bits into pills).

Not a game but still enjoy!

DRAM Tester for MZ-80 K/A and MZ-1200

New DRAM failure detection method.

DRAM Tester for MZ-80 K/A and MZ-1200

Contains IPL.ROM to burn on a 4KB (E)EPROM and to replace M-ROM until DRAM replacement is effective.