473
16-bit Multi-Purpose Timer G (TMG)
Chapter 13
Preliminary User’s Manual U17566EE1V2UM00
13.9 Edge Noise Elimination
The edge detection circuit has a noise elimination function. This function
regards:
• a pulse
not wider
than 1 count clock
period as a
noise
, and does not
detect it as an edge.
• a pulse
not shorter than 2 count clock
periods is detected normally as an
edge
.
• a pulse
wider than 1 count clock period but shorter than 2 count clock
periods may be
detected as an edge or may be eliminated as noise
,
depending on the timing.
(This is because the count-up signal of the counter is used for sampling
timing.) The upper figure below shows the timing chart for performing edge
detection. The lower figure below shows the timing chart for not performing
edge detection.
Basic settings (x = 0, 1 and y = 0 to 5):
Figure 13-20
Timing of edge detection noise elimination
Bit
Value
Remark
CSEx2
0
Count clock =
f
SPCLK0
/4
CSEx1
1
CSEx0
0
IEGny1
1
detection of both edges
IEGny0
1
t+2
t+3
t+4
t+5
t+6
t+7
t+6
t
t+1
t+4
t+2
t+4
t+5
t
t+1
t+3
t+6
t+7
<Timing chart for performing e dge de tection>
<Timing chart for nois e el imination>
TMGn0/TMGn1
TIGny
INTTGnCCy
GCCny
f
COUNTx
TMGn0/TMGn1
TIGny
INTTGnCCy
GCCny
f
COUNTx
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