In his NES Cart Types document, Kevin Horton makes the following statement:
--
PPU access: You have A0-A13, /A13, D0-D7, /WR and /RD. A13 is usually
connected to /CE of the CIRAM to enable it for addresses 0000-1FFF.
Likewise, /A13 is usually used to enable the C-ROM or C-RAM on the cart
(which is then mapped into 2000-3FFF).
--
Inspection of an NROM cart (Baseball) shows A13 and /A13 used just as he indicates. However, every NES memory map I have seen shows the pattern tables in 0000-1FFF and the name/attribute tables beginning at 2000. Isn't something backwards here? Or am I mistaken in thinking that the name/attribute tables are stored in CIRAM? The CHR chip on the cart is definitely a ROM, as CHR /WR is unconnected on the cart.
Thanks,
tex1138 (still trying to get my account activated)
--
PPU access: You have A0-A13, /A13, D0-D7, /WR and /RD. A13 is usually
connected to /CE of the CIRAM to enable it for addresses 0000-1FFF.
Likewise, /A13 is usually used to enable the C-ROM or C-RAM on the cart
(which is then mapped into 2000-3FFF).
--
Inspection of an NROM cart (Baseball) shows A13 and /A13 used just as he indicates. However, every NES memory map I have seen shows the pattern tables in 0000-1FFF and the name/attribute tables beginning at 2000. Isn't something backwards here? Or am I mistaken in thinking that the name/attribute tables are stored in CIRAM? The CHR chip on the cart is definitely a ROM, as CHR /WR is unconnected on the cart.
Thanks,
tex1138 (still trying to get my account activated)