V9938 manual wrong sprite documentation?

By DarkSchneider

Paladin (862)

DarkSchneider's picture

13-07-2016, 09:29

Hi, I wanted to put the VSAT on 0x4200 VRAM address for SC4. Looking at V9938 manual, this should be done by setting R#5 = 0x84 and R#11 = 0.

Looking at bitmap modes, we can see (and tested) that the last 3 bits of R#5 must be set to 1. But it is not the case for SC4, it tells nothing about that. Also, in sprite mode 2 section tells nothings about setting any bits on any register. But the sprite colors show wrong until I set the last 3 bits of R#5 to 1 (R#5 = 0x87) even in SC4.

But with R#5 = 0x87 is really another address, but it shows the colors correctly...what?!
I have to say that I copy manually the color data to 0x4000 and attributes to 0x4200, so there is no "magic" from "put sprite" functions. And everything is shown correctly.

A mistake of V9938 manual?

Login or register to post comments

By madscient

Master (179)

madscient's picture

13-07-2016, 17:22

See the section named "SPRITE MODE 2" (page 91, in Aug 1985 version)

By DarkSchneider

Paladin (862)

DarkSchneider's picture

14-07-2016, 08:55

madscient wrote:

See the section named "SPRITE MODE 2" (page 91, in Aug 1985 version)

Exactly in page 93. In SM2 R#5 requires the last 2 bits to be set to 1, and A9 must always be set to 1. Then the "revised" manual has missing information. Be careful!