2 replies to this topic

[Random Terrain]

This thread is based on this post:

http://www.atariage....58#entry2371858

SpiceWare, on Wed Sep 14, 2011 9:45 AM, said:

The registers like AUDV1, GRP0, NUSIZ1, etc are write-only. You can't read what's been put in them.

I went Googling for "write-only" and "Atari 2600" and found the TIA - WRITE ADDRESS SUMMARY (Write only) list on this page:

http://nocash.emubas...#memoryandiomap


The following is an adapted version of that list for batari Basic users:

NUSIZ0  number-size player-missile 0
NUSIZ1  number-size player-missile 1
COLUP0  color-lum player 0 and missile 0
COLUP1  color-lum player 1 and missile 1
COLUPF  color-lum playfield and ball
COLUBK  color-lum background
CTRLPF  control playfield ball size & collisions
REFP0   reflect player 0
REFP1   reflect player 1
PF0	playfield register byte 0
AUDV0   audio volume 0
AUDV1   audio volume 1
AUDC0   audio control 0
AUDC1   audio control 1
AUDF0   audio frequency 0
AUDF1   audio frequency 1

Except for Superchip RAM, is that a complete list of write-only addresses for batari Basic?


Thanks.

Edited by Random Terrain, Wed Sep 21, 2011 10:50 PM.

[alex_79]

All TIA registers (and a few RIOT ones) are either read-only or write-only.
In fact the same address is usually shared by two registers. For example, address $0008 is COLUBK if you write into it, and INPT0 (paddle line 0) if you read from it.
You can find a complete 2600 memory map, including all TIA and RIOT registers in this post.

[Random Terrain]

alex_79, on Thu Sep 22, 2011 2:43 PM, said:

All TIA registers (and a few RIOT ones) are either read-only or write-only.
In fact the same address is usually shared by two registers. For example, address $0008 is COLUBK if you write into it, and INPT0 (paddle line 0) if you read from it.
You can find a complete 2600 memory map, including all TIA and RIOT registers in this post.

Thanks.