4LS5K datasheet(57/115 Pages) AMSCO

57 / 115 page

Document Feedback

4LS

Digital Interface

Datasheet

• PUBLIC

DS000542

• v3-01 • 2022-Nov-17

114

│ 56

To use the interface, first the N_CS signal should go low, then the word should be sent synchronous

with the SCLK. The data is captured at the MOSI input with the rising edge of SCLK and is sent out on

the MISO output on the falling edge of SCLK.

The updating of registers on the sensor can be made using three different methods: update request,

immediate update and force update. The update request and immediate update are both set by

memory to effective is only performed with falling edge of LVAL signal. In the case of immediate

update the read/write operation from shadow memory to effective is performed immediately,

independently if the sensor is performing integration, A/D conversion or readout.

The Force Update1 method is similar to the immediate update, but is given as an external signal (pulse

with 2 x TMCLK minimum). Force Update updates the register values in the moment that pulse is

applied. Therefore, when using Force Update signal, please make sure that LVAL is low, avoiding

defect lines.

8.2.2

Writing Operation

The writing operation is performed by sending the word containing the data and the address and no

acknowledge signal or indication is given back. It can be performed continuously. When writing to the

registers, the last word to be sent to the register has to be always the update request or immediate

update or force update (STS1Reg

– 0x01), otherwise the write is not performed.

After the last word of data is sent to SPI interface, the SCLK should be maintained during 4 x TSCLK.

Figure 81 exemplifies how to perform the operation over the interface.

Figure 81:

Write Cycle Over SPI Interface

Figure 82 exemplifies a cycle of multiple writing operations.

1 Despite the fact Force Update works properly, Immediate and Update Request are the recommended ones.

4 x TSCLK

N_CS

SCLK

MOSI

4 x TSCLK

4LS5K Datasheet(PDF) 57 Page - ams AG