PC87591L datasheet(108/437 Pages) NSC

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Embedded Controller Modules (Continued)

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Pending Flags

An occurrence of a trigger condition for the Multi-Input Wake-Up input is latched into the respective pending bit in WKPNDx

signal.

Since the WKPNDx register holds a pending wake-up condition until it is cleared, the device does not enter the IDLE mode

if any wake-up bit is both enabled and pending. Consequently, the pending flags must be cleared before an attempt to enter

the Idle mode.

Input Enable

The MIWU utilizes multiple Multi-input Wake-Up signals. Setting the appropriate bits in the WKENAx registers select which

particular wake-up signal causes the device to exit Idle mode.

Interrupts

The combined output of all pending and enabled channels of the MIWU module generates the wake-up signal, which is fed

into both the Power Management Control module (PMC) and the Interrupt Control Unit (ICU). Therefore, each wake-up of

the device can be followed by a wake-up interrupt. Since the device can not enter the power reduction mode without having

the core execute a “WAIT” instruction, a wake-up interrupt is needed to terminate the “WAIT” instruction on wake-up.

MIWU outputs WKO10 through WKO37 may be connected to the Interrupt Control Unit (ICU) to generate an interrupt asso-

ciated with the specific MIWU output. The WKOxx behaves as follows:

●

When the respective WKENxx bit is cleared, the WUIxx is connected to the ICU directly (bypassing the edge detec-

tors and pending bits). The ICU can be conﬁgured to use the signal as a level or edge triggered interrupt.

●

When the respective WKENxx bit is enabled, the output of the pending bit, WKPDxx, is connected to WKOxx.

Note: To enable and disable ICU interrupts generated by their associated WKOxx output of the MIWU, use the ICU mask

In addition, the MIWU provides four interrupt request lines: WKINTA, WKINTB, WKINTC and WKINTD (see Figure 32 on

page 107). These are routed to the ICU (except WKINTB) and can request an interrupt if a valid trigger condition occurred

on any of the enabled input sources within the group of eight inputs associated with the interrupt line. For a detailed summary

of the interrupts available, see Table 17 on page 105.

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