11.13 Operation Of Noise Filter - Fujitsu 8FX Hardware Manual

CHAPTER 11 8/16-BIT COMPOSITE TIMER

11.13 Operation of Noise Filter

11.13 Operation of Noise Filter
This section describes the operation of the noise filter of the 8/16-bit composite
timer.
When the input capture function or PWC timer function is selected, a noise filter can be used to
eliminate the pulse noise of the signal from the external input pin (ECn). H-pulse noise, L-
pulse noise, or H/L-pulse noise elimination can be selected by the FE11, FE10, FE01 and FE00
bits in the TMCRn register. The maximum pulse width that can be eliminated is three machine
clock cycles. If the noise filter function is activated, the signal input will be delayed for four
machine clock cycles.
Sampling
filter clock
External
input signal
Output filter
"H" noise
Output filter
"L" noise
Output filter
"H"/"L" noise
158
Figure 11.13-1 Operation of Noise Filter
FUJITSU SEMICONDUCTOR LIMITED
MB95630H Series
MN702-00009-2v0-E