NEC mPD780973 Series Preliminary User's Manual page 211

Figure 17-5. Sound Generator Amplitude Register (SGAM) Format
Address: FF96H After Reset: 00H
Symbol 7
SGAM 0 SGAM6
SGAM6 SGAM5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
Cautions 1. When rewriting the contents of SGAM, the timer operation does not need to be
stopped. However, note that a high level may be output for one period due to rewrite
timing.
2. Bit 7 must be set to 0.
CHAPTER 17 SOUND GENERATOR
R/W
6 5 4
SGAM5 SGAM4
SGAM4 SGAM3
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 1
0 0 1
0 0 1
0 0 1
0 0 1
0 0 1
0 0 1
0 0 1
0 1 0
0 1 0
0 1 0
0 1 0
0 1 0
0 1 0
0 1 0
0 1 0
0 1 1
0 1 1
0 1 1
0 1 1
0 1 1
0 1 1
0 1 1
1 1 1
3 2
SGAM3 SGAM2 SGAM1
SGAM2 SGAM1 SGAM0
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
1 0
SGAM0
Amplitude
0/128
2/128
3/128
4/128
5/128
6/128
7/128
8/128
9/128
10/128
11/128
12/128
13/128
14/128
15/128
16/128
17/128
18/128
19/128
20/128
21/128
22/128
23/128
24/128
25/128
26/128
27/128
28/128
29/128
30/128
31/128
128/128
211