Subject: RE: [stella] Questions of a graphic nature From: "John Saeger" <john@xxxxxxxxxxx> Date: Sun, 29 Aug 1999 23:55:05 -0700 |
> Does anyone have a comprehensive memory map for the VCS? (including all > the mirrors of various parts?) It would be really helpful, especially > when doing in-cart hardware. There are so many copies of the TIA registers, RAM and such that it would be impractical to draw it out as a map. Hopefully you know what I mean by the 1000 bit, the 200 bit and the 80 bit in hex. These are the important addressing bits. If the 1000 bit is set then it is a ROM (cart) access. Otherwise it is either a TIA, RIOT register or RAM access. The rules to decide which is accessed are: If the 200 bit is set and the 80 bit is set then it's a RIOT register access. If the 200 bit is not set and the 80 bit is set then it's a RAM access. If the 200 bit is not set and the 80 bit is not set then it's a TIA access. As a general rule, it's probably a good idea to only trigger in-cart hardware if the 1000 bit is set. John -- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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