Atari 400 Technical Reference Manual page 467

PITCH VALUES FOR THE MUSICAL NOTES-AUDCTL =0, AUDC = hex AX
AUDF
Hex Dec
HIGH C 1D
29
NOTES B IF 31
AI!
or Bb 21 33
A 23
35
GI!
or Ab 25 37
G 28 40
FI!
or Gb 2A 42
F 2D 45
E 2F 47
DI!
or Eb 32 50
D 35
53
cl! or Db 39 57
C 3C 60
B 40 64
All
or Bb
44
68
A 48
72
GI!
or Ab 4C
76
G 51 81
FI!
or Gb 55 85
F
5B 91
E
60 96
DII
or Eb 66 102
D 6C 108
cil or Db 72 114
MIDDLE C C 79
121
B
80 128
All
or Bb 88 136
A 90
144
Gil or Ab
99
153
G A2
162
FII
or Gb
AD
173
F
B6 182
E
C1 193
DII
or Eb
ce
204
D D9 217
LOW
ell or Db E6 230
NOTES
e
F3
243
STlMER (Start Timer) (D209): This write address resets all audio
frequency dividers to their "AUDF" value. These dividers generate timer
interrupts when they count down to zero (if enabled by IRQEN). (also see
IRQST)
not used
RANDOM (Random Number Generator) (D20A): This address reads the high
order 8 bits of a 17 bit polynomial counter
(9
bit, if bit 7 of AUDCTL=1).
D7 D6 D5 D4 D3 D2
Dl
I
DO
I
111.14