I am also confused by this? Why does it have 11 bits if the PCE can't use 8x8 sprites?
Like tepples said, it intended to use 128ko of VRAM ..
And those 11bits are not the same for sprite cells size, those are in another word (the fourth),it's 11 bits for sprite patterns addresses in VRAM only.
@espozo: if this can help you:
Code: Select all
Here's what a SATB entry looks like:
+---------------------------------------------------------------+
|15 |14 |13 |12 |11 |10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+-----------------------+---------------------------------------+
| | y coordinate |
+-----------------------+---------------------------------------+
| | x coordinate |
+-------------------+---+---------------------------------------+
| | pattern address |
+---+---+-------+---+-------+---+---+-----------+---------------+
| Y | | CGY | X | |CGX|PRI| | palette index |
+---+---+-------+---+-------+---+---+-----------+---------------+
Y -> vertical flip bit (0 = normal, 1 = reversed)
X -> horizontal flip bit (0 = normal, 1 = reversed)
CGY -> sprite height: 00 = 16
01 = 32
10 = invalid
11 = 64
CGX -> width: 0 = 16
1 = 32
PRI -> priority flag: 0 = in background
1 = in foreground
What, were they unsure?
Yes it's sure, you can use slow/fast VRAM with VDC(it's designed for), and you can also use a 8/16 bits CPU, you can switch all VDC's registers in 16 bits mode instead of 2 8 bits with a connected pin to +VCC .
I think the VDC was not designed specificaly for PCE, but for general uses in multiple systems .
Slow VRAM can not be used for PCE's med/hi res,even with his 100ns VRAM, still works under speed specifications for hires (93ns is required),but works .