
318
Chapter 8
16-Bit Timer/Event Counter Q
User’s Manual U16702EE3V2UD00
(7)
TIQnm pin noise elimination control register n (QnmNFC)
The QnmNFC register is an 8-bit register that sets the digital noise filter of the timer Q input pin.
This register can be read or written in 8-bit or 1-bit units.
RESET input clears this register to 00H.
Figure 8-13:
TIQnm Pin Noise Elimination Control Register n (QnmNFC) Format
Cautions: 1. Be sure to clear bits 3 to 5 and 7 to 0.
2. A signal input to the timer input pin (TIQnm) before the QnmNFC register is set is
output with digital noise eliminated. Therefore, set the sampling clock (NFC2 to
NFC0) and the number of times of sampling (NFSTS) by using the QnmNFC
register, wait for initialization time = (Sampling clock)
×
(Number of times of
sampling), and enable the timer operation.
Remarks: 1.
The width of the noise that can be accurately eliminated is (Sampling clock)
×
(Number
of times of sampling – 1). Even noise with a width narrower than this may cause a
miscount if it is synchronized with the sampling clock.
2.
n: Number of timer channels (0, 1)
m: Number of input pins (0 to 3)
Address: Q00NFC: FFFFFB50H (TIQ00 pin)
Q01NFC: FFFFFB54H (TIQ01 pin)
Q02NFC: FFFFFB58H (TIQ02 pin)
Q03NFC: FFFFFB5CH (TIQ03 pin)
Q10NFC: FFFFFB60H (TIQ10 pin)
Q11NFC: FFFFFB64H (TIQ11 pin)
Q12NFC: FFFFFB68H (TIQ12 pin)
Q13NFC: FFFFFB6CH (TIQ13 pin)
Symbol
7
6
5
4
3
2
1
<0>
Address
R/W
After
reset
QnmNFC
0
NFSTS
0
0
0
NFC2
NFC1
NFC0
FFFFFB50H
to
FFFFFB6CH
R/W 00H
NFSTS
Selection of sampling times number for digital noise filtering
0
3 times
1
2 times
NFC2
NFC1
NFC0
Sampling clock selection
0
0
0
fxx
0
0
1
fxx/2
0
1
0
fxx/4
0
1
1
fxx/16
1
0
0
fxx/32
1
0
1
fxx/64
Other than above
Setting prohibited
electronic components distributor