HARDWARE ManualVDP2 User's ManualChapter 3 RAM
BackForward
VDP2 User's Manual / Chapter 3 RAM / ■ 3.3 How to access VRAM during the display period

● Access to vertical cell scroll table data

When using the vertical cell scroll function in NBG0 and NBG1, the vertical cell scroll table data must be read in addition to the pattern name data and character pattern data (bitmap pattern data). Vertical cell scroll table data read access is required once per cycle per page. Vertical cell scroll table data read access for NBG0 must be specified at the timing of T0 or T1, and vertical cell scroll table data read access for NBG1 must be specified at the timing within T0 to T2. Hmm. Also, the access for NBG0 and NBG1 must be in the same bank, and the access for NBG0 must be specified first.
When specifying the same vertical cell scroll table data read access for multiple banks, it must be specified at the same access timing.
Figure 3.5 shows the access specification restrictions for vertical cell scroll table data.

Figure 3.5 Access specification restrictions for vertical cell scroll table data


BackForward
HARDWARE Manual VDP2 User's ManualChapter 3 RAM
Copyright SEGA ENTERPRISES, LTD., 1997