ZSSC3123AI2R datasheet(30/67 Pages) RENESAS

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ZSSC3123 Datasheet

August 16, 2018

10.3.2 Sleep Mode

In Sleep Mode, the digital core will only perform conversions when the ZSSC3123 receives a Measurement Request command (MR); otherwise,

the ZSSC3123 is always powered down. Measurement Request commands can only be sent using I2C or SPI, so PDM is not available. The

Alarms can be used in Sleep Mode but only in combination with I2C or SPI. More details about MR commands in Sleep Mode operation can be

found in section 10.3.2.1.

Note: Sleep Mode power consumption is significantly lower than Update Mode power consumption (see section 5 for exact values).

The following figure shows the measurement and communication sequence for Sleep Mode. The master sends an MR command to wake the

ZSSC3123 from power down. After the ZSSC3123 wakes up, a measurement cycle is performed consisting of both a temperature and a

capacitance conversion followed by the DSP correction calculations.

At the end of a measurement cycle, the digital output register and Alarms will be updated before powering down. An I2C or SPI data fetch (DF)

is performed during the power-down period to fetch the data from the output register. In I2C the user can send another MR to start a new

measurement cycle without fetching the previous data, but in SPI, a DF must be done before another MR can be sent. After the data has been

fetched, the ZSSC3123 remains powered down until the master sends an MR command.

Figure 15. Measurement Sequence in Sleep Mode (Only I2C, SPI, or Alarms)

Note: See section 10.2 for timing of measurements.

Command wakes ZSSC3123

ZSSC3123

Core Activity

Serial Interface

Activity

Cap

Calc

Write new corrected signal measurement to

output register (I2C, SPI, Alarms)

Cap

Conv

Temp

Conv

Power

Down

Power Down

Valid read

occurs

Temp

Calc

ZSSC3123AI2R Datasheet(PDF) 30 Page - Renesas Technology Corp