SM8230A_06 Datasheet, PDF (6/8 Pages) NEC – 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× multi-
ples of 480kHz. The input code and the corresponding clock frequency are shown in table 1.
Table 1. CK command
CK1
CK0
CLK input clock frequency
0
0
480kHz
0
1
960kHz
1
0
1.92MHz
1
1
3.84MHz
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 deviation are shown in
tables 2 and 3. Note that the design value and frequency deviation are calculated values assuming a deviation-
free system clock input on CLK.
Table 2. FH command
FH1
FH0
DTMF frequency [Hz]
Design value [Hz]
Deviation [%]
0
0
1209
1212.1
+0.26
0
1
1336
1333.3
−0.20
1
0
1477
1481.5
+0.30
1
1
1633
1632.7
−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
SEIKO NPC CORPORATION —6