CS5376-BS View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS5376-BS

Low Power Multi-Channel Decimation Filter

Cirrus Logic 

CS5376

4. RESET CONTROL

When the RESET signal is released, the CS5376

automatically performs a series of self-tests. De-

pending on the state of the BOOT pin, it then either

actively boots from EEPROM or waits for config-

uration information to be written by a microcon-

troller.

4.1 Reset Pin Descriptions

RESET - Pin 55

RESET is an active low signal that places the

CS5376 into a reset state when asserted.

BOOT - Pin 56

The BOOT signal selects how the CS5376 loads

configuration information. The logic state of this

pin is latched 1 µs after RESET is released to select

between coprocessor or stand-alone boot modes. A

logical low selects coprocessor boot mode, a logi-

cal high selects stand-alone boot mode.

4.2 Boot Configurations

When booting in coprocessor mode, a microcon-

troller or other SPI bus master is required to write

configuration information. When booting in stand-

alone mode, the CS5376 reads configuration infor-

mation from EEPROM and no microcontroller is

required. A hybrid mode can also be used which

reads an initial configuration from EEPROM and

then writes changes using a microcontroller.

Coprocessor Mode

Coprocessor mode is designed for systems required

to run multiple configurations from a common set

of hardware. The ability to change configurations

in real time gives maximum flexibility in the field.

This mode requires a microcontroller or other SPI

bus master to be connected to the CS5376 SPI 1

port. The microcontroller can rewrite the filter co-

efficients, change the filter output stage, enable and

disable the test bit stream, and manually update the

gain and offset correction values during operation.

To set the CS5376 configuration, the microcontrol-

ler writes a series of command and data values to

the decimation engine through the SPI 1 port. See

“Serial Peripheral Interface 1” on page 21 for more

information on connecting a microcontroller to the

SPI 1 port.

Stand-Alone Mode

If the CS5376 is designed into a system with a fixed

configuration, no microcontroller is required.

Stand-alone mode boots from EEPROM to a fixed

configuration and immediately begins operation.

The EEPROM contains all configuration informa-

tion including filter coefficients, register settings,

and test bit stream data.

It might not be possible to know the gain and offset

correction values in advance of deploying a system.

If the configuration EEPROM is in-circuit repro-

grammable, the system can be booted with offset

and gain correction disabled and the appropriate

correction values calculated. The new correction

values can then be programmed into the EEPROM

and the CS5376 re-booted with gain and offset cor-

rection enabled.

See “Serial Peripheral Interface 1” on page 21 for

more information on booting from a configuration

EEPROM, and the format required for EEPROM

data.

Hybrid Mode

A boot configuration that requires more engineer-

ing effort to implement is a hybrid

coprocessor / stand-alone boot mode. In hybrid

mode the CS5376 initially boots in stand-alone

mode from a configuration EEPROM. After boot-

ing, a microcontroller updates the configuration in-

formation in coprocessor mode by writing

commands to the decimation engine through the

SPI 1 port.

Hybrid mode is more complex at the system level

because it requires the ability to tri-state the micro-

DS256PP1

18

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