Keyboard v1.1 ghosting

[zomgugoff]

When typing "cd " quickly, the cursor moves to the beginning of the line. I believe this is the result of keyboard ghosting. There are no diodes running from each row->column junction to prevent it. The Yellow MSX keyboard matrix does this and has no ghosting issues.

Yellow MSX keyboard schematic

[skiselev]

The Omega MSX has only 3 diodes to prevent ghosting, these are only used for the modifier keys: Shift, Code, Graph.
I think this is similar to what most commercial MSX systems do.
With that said, I am having difficulty understanding why pressing C and D quickly will result in ghosting. Ghosting usually happens when three or more keys are pressed simultaneously. You're not supposed to press C and D simultaneously, and even if you do, these are only two keys.

[zomgugoff]

You are correct in that pressing only C and D does not result in ghosting. The text I quoted includes a space after D, which is the 3rd key. The combination of these 3 keys activates the same column/row pins as the Home key. I have hacked in a couple diodes for these keys since then as these are the most common ones I type in DOS and that did stop mis-triggering a Home key press.