Atari 400 Technical Reference Manual page 459

DLISTL and DLISTH should be changed only during vertical blank or with
DMA disabled. Otherwise, the screen may roll. Bit 7 of NMIEN must be set
in order to receive display list interrupts.
CHBASE (Character Address Base Register) (D409): This address writes
data into the Character Address Base Register. The data specifies the most
significant byte (MSB) of the address of the desired character set (see
section II). Note that the last 1 or 2 bits are assumed to be O.
40 Character Modes
ID7 ID6 IDs~4 ID3 ID2 I
* CHBASE
"lC:
)
CIS
113
2
2
110
t:
9
114 III
I
8
I 7 I 6 I
5 4
"""' "
Base Address
Char Name
Line Counter
20 Character Modes
!D7 ID6 IDS
~D4
ID3 ID2 ID1
J
*
CHBASE
.......,.,.
(15
114 113
Ig!ll
110 9
~8
I 7 I 6
:::5
4
3
Jd222iJ
Base Address Char Name Line Counter
Os SHADOW: CHBAS (2F4)
PMBASE (Player-Missile Address Base Register) (D407): This address
writes data into the Player-Missile Address Base Register. The data
specifies the MSB of the address of the player and missile DMA data (see
section II).
One Line Resolution
ID7 ID6 IDS ID4 ID3 I not used PMBASE
..........
~
~5
114
1~112
6 I 5
I
42::
3
I
2
I 1 I
0
]
)
Base Address Player-Missile Player-Missile Scan
Select Counters
Two Line Resolution
~7
ID6 IDs~4 ID3 ID2 I
* PMBASE
")
65
113:g2
110~
}
114 III
6
5
I 4
I
3 I 2
I 1 I 0
...
"""
Base Address Player-Missile Player-Missile Scan
Select Counter
*
=
Not Used
111.6