SM8230A Datasheet, PDF (6/7 Pages) Nippon Precision Circuits Inc – Tone Dialer with Built-in Piezo Driver

SM8230A
Transfer Command Specifications
The transfer data code format is shown in figure 3.
Data is transferred with the MSB as the leading bit.
The data sets the input clock, high-frequency group
and low-frequency group frequencies, and the output
levels. The commands are shown in tables 1 to 4.
b15(MSB)
b0(LSB)
0 0 CK1 CK0 FH1 FH0 GH3 GH2 GH1 GH0 FL1 FL0 GL3 GL2 GL1 GL0
Low group output level set.
Low group frequency set.
High group output level set.
High group frequency set.
CLK pin input frequency set.
Set (b14, b15) = (0, 0)
for normal operation.
Figure 3. Transfer command format
CK command (CK1, CK0)
These bits set the frequency of the input clock on
CLK. The frequency can be set to 1×, 2×, 4×, and 8×
multiples of 480 kHz. The input code and the corre-
sponding clock frequency are shown in table 1.
Table 1. CK command
CK1
CK0
0
0
0
1
1
0
1
1
CLK input clock frequency
480 kHz
960 kHz
1.92 MHz
3.84 MHz
FH/FL command (HF1, FH0 / FL1, FL0)
These bits set the DTMF signal high-frequency and
low-frequency group frequencies, respectively.
The input code, the corresponding group frequency
specification, the design value and frequency devia-
tion are shown in tables 2 and 3.
Note that the design value and frequency deviation
are calculated values assuming a deviation-free sys-
tem clock input on CLK.
Table 2. FH command
FH1 FH0
0
0
0
1
1
0
1
1
DTMF
frequency
(Hz)
1209
1336
1477
1633
Design
value (Hz)
1212.1
1333.3
1481.5
1632.7
Deviation
(%)
+0.26
−0.20
+0.30
−0.02
Table 3. FL command
FH1 FH0
0
0
0
1
1
0
1
1
DTMF
frequency
(Hz)
697
770
852
941
Design
value (Hz)
697.7
769.2
851.1
937.5
Deviation
(%)
+0.10
−0.10
−0.11
−0.37
NIPPON PRECISION CIRCUITS—6