ZSSC3218 datasheet(21/56 Pages) RENESAS

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ZSSC3218 Datasheet

April 20, 2016

3.4.

Operational Modes

Figure 3.2 illustrates the ZSSC3218 power-up sequence and subsequent operation depending on the selected

interface communication mode (I

2C™ or SPI) as determined by interface-related first activities after power-up or

reset. If the first command after power-up is a valid I²C™ command, the interface will function as an I²C™

interface until the next power-on-reset. If there is no valid I²C™ command, but an active signal at the SS pin is

detected as the first valid activity, then the interface will respond as an SPI slave. With either interface, after the

voltage regulators are switched on, the ZSSC3218’s low-voltage section (LV) is active while the related interface

configuration information is read from memory. Then the LV section is switched off, the ZSSC3218 goes into

Sleep State, and the interface is ready to receive commands. The interface is always powered by VDD, so it is

referred to as the high voltage section (HV).

See Table 3.1 for definitions of the commands.

Figure 3.3 shows the ZSSC3218 operation in Normal Mode (with two operation principles: “Sleep” and “Cyclic”)

and Command Mode, including when the LV and HV sections are active as indicated by the color legend. The

Normal Mode automatically returns to Sleep State after executing the requested measurements, or periodically

wakes up and conducts another measurement according to the setting for the sleep duration configured by

CYC_period (bits[14:12] in memory register 02HEX). In Command Mode, the ZSSC3218 remains active if a

dedicated command (Start_NOM) is sent, which is helpful during calibration. Command Mode can only be

entered if Start_CM is the first command received after POR.

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