ZAMC4100GA2R datasheet(44/156 Pages) RENESAS

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ZAMC4100 Datasheet

January 26, 2016

3.5.2.

SLEEP Mode

In SLEEP Mode, current consumption is very low, less than 80µA. The MCU chip is powered-down and the SBC

supports only the functionality necessary for detecting a LIN wake-up or WDT wake-up event (see section 3.5.4).

In this mode, all drivers are automatically disabled. The MCU enables SLEEP Mode by setting the SLEEP bit in

the SMDCTRL register (Table 3.5). SLEEP Mode is exited if the SBC detects a wake-up event from the LIN bus

and consequently it re-activates the MCU as well as re-enabling the drivers.

Figure 3.7 shows the system behavior when the SLEEP Mode is enabled. The procedure starts with switching-off

the MCU supply and SBC analog blocks supply. In order to minimize power consumption, the SBC digital clock

switches to the OSCL (125kHz).

Important note: If there is a failure in the OSCL (see section 3.2), the SLEEP Mode entry command is ignored.

As a result, the system avoids undefined states with a powered-off MCU but with power supplied for the analog

circuitry (see SLEEP Mode entry flow in Figure 3.7).

When a valid LIN wake-up is detected, the SBC chip starts the procedure for returning to the NORMAL Mode.

During this procedure, the analog blocks are powered-up, the SBC digital clock is switched to 4MHz, and the

MCU supply is enabled. Before enabling the MCU clock and releasing the MCU reset, the SBC performs an MCU

supply check that is the same as the checks at system start-up. If the MCU supply voltages are in range, it starts

operating; otherwise the system switches back to SLEEP Mode.

Important notes:

1) Activation of a driver immediately after wake-up from Sleep Mode is not possible due to the relatively slow

settling time of the charge pump (see parameter tCP_STL in Table 1.17). The CP condition is continuously

monitored by the CPVEIF flag, which can be auto-cleared when a stable CP voltage is present if that

functionality is enabled. Refer to section 3.4.4 for more details regarding charge pump voltage monitoring.

2) When SLEEP Mode is enabled, all drivers are automatically disabled. If needed, after wake-up the MCU

should re-enable the drivers by setting the corresponding enable bits.

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