SM8230A

SEIKO NPC CORPORATION —6

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.

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.

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.

Figure 3. Transfer command format

Table 1. CK command

CK1

CK0

CLK input clock frequency

0

0

480kHz

0

1

960kHz

1

0

1.92MHz

1

1

3.84MHz

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

DTMF frequency [Hz]

Design value [Hz]

Deviation [%]

0

0

697

697.7

+0.10

0

1

770

769.2

−0.10

1

0

852

851.1

−0.11

1

1

941

937.5

−0.37

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.

b15 (MSB)

b0 (LSB)

Set (b14, b15) = (0, 0)

for normal operation.