SM6452AM/BM

NIPPON PRECISION CIRCUITS—10

MICROCONTROLLER INTERFACE

SM6452AM

Transfer format

The SM6452AM uses a 3-wire serial interface to select channels and set attenuation levels. The transfer format

is shown in figure 1.

Data is shifted into the internal shift register on the rising edge of MCK, and the attenuation value is loaded and

changed on the rising edge of MLEN. Accordingly, data on MDT should be changed on the falling edge of

MCK. The dotted lines for MCK and MLEN also indicate valid timing.

Data description (D15 to D0)

s

D15, D14

Don’t care.

s

D13 to D8

Chip address bits. Each of 6 channels is set when the corresponding bit is set HIGH.

• D13: channel 1

• D12: channel 2

• D11: channel 3

• D10: channel 4

• D9: channel 5

• D8: channel 6

s

D7 to D0

Gain/attenuation set bits. The gain/attenuation setting for ATT register settings are shown in table 1.

Figure 1. Microcontroller input data timing

MDT

MCK

MLEN

D15 D14 D13 D12 D11 D10 D9

D8

D7

D6

D5

D4

D3

D2

D1

D0