K60P100M100SF2RM Datasheet, PDF (1032/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Functional Description
Note
It is expected the output mask feature be used only in combine
mode.
39.4.16 Fault Control
The fault control is enabled if (FTMEN = 1) and (FAULTM[1:0] ≠ 0:0).
FTM can have up to four fault inputs. FAULTnEN bit (where n = 0, 1, 2, 3) enables the
fault input n and FFLTRnEN bit enables the fault input n filter. FFVAL[3:0] bits select
the value of the enabled filter in each enabled fault input.
First each fault input signal is synchronized by the system clock (see the synchronizer
block in the following figure). Following synchronization, the fault input n signal enters
the filter block. When there is a state change in the fault input n signal, the 5-bit counter
is reset and starts counting up. As long as the new state is stable on the fault input n, the
counter continues to increment. If the 5-bit counter overflows (the counter exceeds the
value of the FFVAL[3:0] bits), the new fault input n value is validated. It is then
transmitted as a pulse edge to the edge detector.
If the opposite edge appears on the fault input n signal before validation (counter
overflow), the counter is reset. At the next input transition, the counter starts counting
again. Any pulse that is shorter than the minimum value selected by FFVAL[3:0] bits (×
system clock) is regarded as a glitch and is not passed on to the edge detector.
The fault input n filter is disabled when the FFVAL[3:0] bits are zero or when
FAULTnEN = 0. In this case the fault input n signal is delayed 2 rising edges of the
system clock and the FAULTFn bit is set on 3th rising edge of the system clock after a
rising edge occurs on the fault input n.
If FFVAL[3:0] ≠ 0000 and FAULTnEN = 1, then the fault input n signal is delayed (3 +
FFVAL[3:0]) rising edges of the system clock, that is, the FAULTFn bit is set (4 +
FFVAL[3:0]) rising edges of the system clock after a rising edge occurs on the fault input
n.
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K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.