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(3) Zero-cross switching control method
The zero-cross switching control method consists of setting the zero-cross control bits to the zero-cross detection
mode (D36, D37 = 0), and specifying the detection blocks (D38, D39) before transmitting the data. These control bits
are latched immediately following data transfer, that is to say beforehand in sync with the falling edge of CE, so when
updating data of volumes, etc., it is possible to perform mode setting and zero-cross switching with one data transfer.
An example of control when updating the data of the volume block is shown below.
D36
D37
0
0
Zero-cross detection
mode setting
(4) Zero-cross timer setting
If the input signal becomes lower than the zero-cross comparator detection sensitivity, or if only low-frequency
signals are input, zero-cross detection continues to be impossible, and data is not latched during this time.
The zero-cross timer can set a time for forcible latch during such a status when zero-cross detection is not possible.
For example, to set 25 ms,
using T = 0.69CR and C = 0.033 µF,
we obtain
25 × 10
–3
R=
0.69 × 0.033 × 10
Normally, a value between 10 ms and 50 ms is set.
(5) Cautions related to serial data transfer
1. To ensure that the high-frequency digital signals transferred to the CL, DI, and CE pins do not spill over to the
analog signal block, either guard these signal lines with a ground pattern, or perform transmission using shielded
wires.
2. The data format of the LC75411ES and 75411WS uses 8-bit addresses and 44-bit data. When sending data using
multiples of 8 (when sending 48 bits), use the method described in Figure 1.
Method for Receiving Data Using Multiple of 8 of LC75411ES and 75411WS
X
X
X
Dummy data
LC75411ES, 75411WS
D38
D39
1
0
Volume block
setting
1.1 MΩ
–6
X
D0
D1
D2
D3
Input switching control
D36
D37
D38
Figure 1
D39
D40
D41
D42
D43
Test mode control
X : don't care
No. 6928-28/33
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