ZAMC4100 datasheet(35/156 Pages) RENESAS

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ZAMC4100 Datasheet

January 26, 2016

Figure 3.2 ZAMC4100 Clock Sources

OSCH

125kHz

OSCL

WDT

LIN

Wake-up

20MHz

4MHz

SLEEP

SBC Clock

MCU Clock

OSCL Failure

Detection

OSCLEIF

OSCL Failure Detection

In order to increase the system robustness, the ZAMC4100 features a mechanism for failure detection in the

OSCL clock generation. This ensures that the MCU is alerted by an interrupt in the event of the watchdog timer

not functioning (caused by an OSCL clock stop).

The OSCL clock is observed by dedicated circuitry running on the OSCH clock. If for any reason the OSCL clock

stops, then an OSCL failure event is detected, captured in the flag OSCLEIF (see Table 3.1), and propagated as

an interrupt to the MCU. Then the MCU firmware can determine whether to perform any failure protection actions

(for example, a failure report to the electronic control unit ECU via LIN) or to continue with the regular firmware

execution.

Note: In SLEEP Mode, the OSCL failure detection is disabled because the OSCH clock is stopped, i.e. no OSCL

clock observation is possible.

3.2.2.

Reset Sources

The ZAMC4100 system has three resets all generated within the SBC chip. Each reset source has its own flag bit.

The MCU can distinguish between the different resets by reading the contents of register RSTSTAT (Table 3.1

and Table 3.2). The flags of the RSTSTAT register are cleared by writing a ‘1’ in the corresponding bit of the

RSTSTAT register.

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