NXP Semiconductors KL25 Series - Freescale Semiconductor, Inc

The only difference in operation between Sampled, Non-Filtered (# 3A) and Sampled,
Non-Filtered (# 3B) is in how the clock to the filter block is derived. In #3A, the clock to
filter block is externally derived while in #3B, the clock to filter block is internally
derived.
The comparator filter has no other function than sample/hold of the comparator output in
this mode (# 3B).
IRQ
INP
INM
FILTER_CNT
INV
COUT
COUT
OPE
SE
CMPO to
PAD
COUTA
1
WE
0
SE=0
CGMUX
COS
FILT_PER
0
0
+
-
FILT_PER
COS
0x01
IER/F CFR/F
WINDOW/SAMPLE
1
0
EN,PMODE,HYSTCTR[1:0]
divided bus clock
CMPO
bus clock
Internal bus
Polarity
select
Window
control
Filter
block
Interrupt
control
To other SOC functions
Clock
prescaler
Figure 29-17. Sampled, Non-Filtered (# 3B): sampling interval internally derived
29.8.1.4 Sampled, Filtered mode (#s 4A & 4B)
In Sampled, Filtered mode, the analog comparator block is powered and active. The path
from analog inputs to COUTA is combinational unclocked. Windowing control is
completely bypassed. COUTA is sampled whenever a rising edge is detected on the filter
block clock input.
The only difference in operation between Sampled, Non-Filtered (# 3A) and Sampled,
Filtered (# 4A) is that, now, CR0[FILTER_CNT]>1, which activates filter operation.
Functional description
KL25 Sub-Family Reference Manual, Rev. 3, September 2012
524 Freescale Semiconductor, Inc.