CS5378 View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS5378

Low-power Single-channel Decimation Filter

Cirrus Logic 

CS5378

Digital Filter

Command

Interpreter

SPI™

Registers

Serial

Pin Logic

SS:EECS

SCK

MOSI

MISO

Figure 17. Serial Interface Block Diagram

9. CONFIGURATION BY MICROCONTROLLER

After reset, the CS5378 reads the state of the

GPIO7:BOOT pin to determine a source for con-

figuration commands. If BOOT is low, the CS5378

receives configuration commands from a micro-

controller.

9.1 Pin Descriptions

Pins required for microcontroller boot are listed

here, other serial pins are inactive.

SS:EECS - Pin 27

Slave select input pin, active low. Serial chip select

input from a microcontroller.

9.2 Microcontroller Hardware Interface

When booting from a microcontroller the CS5378

receives configuration commands and configura-

tion data through serial transactions, as shown in

Figure 18. 8-bit SPI opcodes and 8-bit addresses

are combined to read and write 24-bit configuration

commands and data.

Microcontroller serial transactions require toggling

the SS:EECS pin as the CS5378 chip select and

writing a serial clock to the SCK input. Serial data

is input to the CS5378 on the MOSI pin, and output

on the MISO pin.

MOSI - Pin 26

Serial data input pin. Valid on rising edge of SCK,

transition on falling edge.

MISO - Pin 25

Serial data output pin. Valid on rising edge of

SCK, transition on falling edge. Open drain output

requiring a 10 kΩ pull-up resistor.

9.3 Microcontroller Serial Transactions

Microcontroller configuration commands are writ-

ten to the digital filter through SPI registers. A 24-

bit command and two 24-bit data words can be

written to the SPI registers in any single serial

transaction. Some commands require additional

data words through additional serial transactions to

complete.

SCK - Pin 24

Serial clock input pin. Serial clock input from mi-

crocontroller, maximum 4.096 MHz.

9.3.1 SPI opcodes

A microcontroller communicates with the CS5378

serial port using standard 8-bit SPI opcodes and an

8-bit address. The standard SPI ‘Read’ and ‘Write’

opcodes are listed in Figure 18.

DS639F2

30

Share Link: