Clock, Reset, and Power Control (CRP)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
5-25
Preliminary
sources. To be used as a low-power mode wakeup, pins must be configured with the output buffer disabled
in the SIU_PCR registers prior to entry into the low-power mode.
Each external pin wakeup source is enabled by the corresponding CRP_WKSE[WKPDETn] field.
External pin wakeup generation can be selected for either a rising edge event on the pin, falling edge, or
both. Using the CRP_WKSE[WKCLKSEL] bit, the edge capture logic can be selectively clocked from
either the 16 MHz IRC clock for faster wakeup, or the 32 kHz IRC clock for lower average power. For
wakeup, the pad assignment in the SIU_PCR does not matter. This enables a pin, such as a CAN receive
pin, to wake up the device on a transition. For example, WKPSEL7 could select PF15, which could be
assigned to CNRX_D.
The corresponding CRP_PSCR[PWKSRCF] flag bit will be set when a selected and enabled event occurs
on an external pin wakeup source. An interrupt request can be generated for an external pin wakeup by
setting the corresponding CRP_PSCR[PWKSRIE] bit. This interrupt request will be pending once the
device recovers from the previous low-power mode.
On exiting stop mode, the PC continues with the location of interrupt service routine of the interrupt that
exits the WAIT instruction. On exiting sleep mode, the PC value is loaded with the value contained in the
Z1VEC/Z0VEC registers. The RECPTR register is a general purpose register which retains a value during
stop and sleep modes and thus may be used by software to hold a generic value used by recovery routines.
A block diagram for the external pin wakeup logic is given in
.
