ZSSC3154 Datasheet

© 2016 Integrated Device Technology, Inc.

13

January 22, 2016

2.3

System Control

2.3.1

Main System Tasks

The calibration microcontroller (CMC) is the central system control unit and supports the following tasks and

features:

• Manage the startup sequence

• Control the measurement cycle regarding to the EEPROM-stored configuration data

• Process the signal conditioning calculation (16-bit calculation for the measured signals using the

ROM-resident signal conditioning formulas and the EEPROM-stored conditioning coefficients)

• Assign the conditioned output values to the analog outputs and control the output behavior

• Process the communication requests received via the digital interfaces

• Perform failsafe tasks and indicate detected errors by setting analog outputs to the diagnostic fault band

2.3.2

General Working Modes

The ZSSC3154 supports three different working modes:

• Normal Operation Mode (NOM) – for continuous processing of the signal conditioning

• Command Mode (CM) – for configuration and calibration and for access to all internal registers

• Diagnostic Mode (DM) – for failure messages

2.4 Normal Operation Mode

A configured and calibrated ZSSC3154 starts the Normal Operation Mode (NOM) immediately after power-on if

there is no communication request within a startup window (refer to the ZSSC3154 Functional Description for

details). It consists of a startup phase, the measurement cycle, the conditioning calculation, and the analog output

for the sensor signals.

2.4.1

Startup Phase

After power-on, the startup phase is processed, which includes

• Settling of the internal supply voltages including the reset of the circuitry

• System start and configuration, EEPROM readout, and signature check

• ROM check, if enabled

• Processing the measurement cycle start routine including all measurements to provide the configured

output signals

• One-wire communication window

If an error is detected during the startup phase, the Diagnostic Mode (DM) is activated and the analog output at

the AOUT1 and AOUT2 pins remains in the diagnostic fault band range.

After the startup phase, the continuously running measurement and sensor signal conditioning cycle is started,

and the analog or digital output of the conditioned sensor signals is activated.