- ページ 3
スイッチ Cypress CE66058のPDF マニュアルをオンラインで閲覧またはダウンロードできます。Cypress CE66058 14 ページ。 Dynamically switch csd bleed resistor
ページを印刷する
The PSoC Designer™ project associated with this code example, Example_Dynamic_Bleed_Resistor
switch the bleed resistor during run time to scan a sensor with a different bleed resistor. This is evaluated using the
CY3280-SLM board. The SLM board has five buttons with different Cp values, as shown in
R
used for the current project is shown in
B
As shown in
Table
1, button 4 has the lowest C
12
Counts = 2
∗ 7.5 ∗ [
In this equation:
Resolution = 12 bits
Ω
Rb = 7.5 k
Sysclk = 24 MHz
Period = 1
REF = 4
Cp = 11 pF
Therefore,
Counts = 4096 ∗ 7.5 ∗ [ 6 ] ∗ [ 1 ] ∗ 11 = 2027
Since the raw count value is 2027, this value is 49 percent of the maximum raw count value. Therefore, to ensure that the raw
count is in the range of 60 to 70 percent of the maximum value, a different Rb is used for button 4.
Using
Equation 3
and
Equation
Rbmax4 =
2
∗[
4∗
Rbmax4 =
24
12
2
∗[
4∗1
0.70
Rbmax4 =
6∗11
www.cypress.com
Table
2.
Table 1. Buttons C
Name
Button 0
Button 1
Button 2
Button 3
Button 4
Table 2. Cmod and Rbx Values
Name
Cmod
Rb1
Rb2
of 11 pF. Using
p
24
1
] ∗ [
− 1] ∗ 11
1
4
4∗1
+
4
16
4:
0.70∗2
1
]∗[
−1]∗
1
+
4
16
12
0.70∗ 2
1
]∗[
−1]∗11
1
4
+
4
16
10.6 kΩ
=
Document No. 001-66058 Rev.*E
Dynamically Switch CSD Bleed Resistor
Values
p
Parasitic Capacitance
16 pF
14 pF
13 pF
14 pF
11 pF
Value
10 nF
7.5 kΩ
10 KΩ
Equation
1, the raw count value for button 4 is calculated as:
Equation 4
,
demonstrates how to
Table
1. The value of CMOD and
3