Lines Matching +full:connected +full:- +full:positive
1 # SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
2 ---
3 $id: http://devicetree.org/schemas/hwmon/ntc-thermistor.yaml#
4 $schema: http://devicetree.org/meta-schemas/core.yaml#
9 - Linus Walleij <linus.walleij@linaro.org>
13 vary in resistance in an often non-linear way in relation to temperature.
16 temperature is non-linear, software drivers most often need to use a look
19 When used in practice, a thermistor is often connected between ground, a
20 pull-up resistor or/and a pull-down resistor and a fixed voltage like this:
22 + e.g. 5V = pull-up voltage (puv)
24 +-+
26 | | Pull-up resistor
28 +-+
29 |-------------------------o
30 +-+ | ^
34 / | | "connected ground"
36 +-+ |
37 |-------------------------o
38 +-+ ^
40 | | Pull-down resistor | Measured voltage (mv)
41 | | (pdo) | "connected positive"
42 +-+ |
48 called "connected ground" and "connected positive" and shall be understood as
49 the cases when either pull-up or pull-down resistance is zero.
51 If the pull-up resistance is 0 one end of the thermistor is connected to the
52 positive voltage and we get the thermistor on top of a pull-down resistor
53 and we take the measure between the thermistor and the pull-down resistor.
55 Conversely if the pull-down resistance is zero, one end of the thermistor is
56 connected to ground and we get the thermistor under the pull-up resistor
57 and we take the measure between the pull-up resistor and the thermistor.
59 We can use both pull-up and pull-down resistors at the same time, and then
60 the figure illustrates where the voltage will be measured for the "connected
61 ground" and "connected positive" cases.
69 - const: epcos,b57330v2103
70 - const: epcos,b57891s0103
71 - const: murata,ncp15wb473
72 - const: murata,ncp18wb473
73 - const: murata,ncp21wb473
74 - const: murata,ncp03wb473
75 - const: murata,ncp15wl333
76 - const: murata,ncp03wf104
77 - const: murata,ncp15xh103
78 - const: samsung,1404-001221
80 - const: ntc,ncp15wb473
82 - const: ntc,ncp18wb473
84 - const: ntc,ncp21wb473
86 - const: ntc,ncp03wb473
88 - const: ntc,ncp15wl333
91 "#thermal-sensor-cells":
95 pullup-uv:
97 description: Pull-up voltage in micro volts. Must always be specified.
99 pullup-ohm:
101 description: Pull-up resistance in ohms. Must always be specified, even
104 pulldown-ohm:
106 description: Pull-down resistance in ohms. Must always be specified, even
109 connected-positive:
111 description: Indicates how the thermistor is connected in series with
112 a pull-up and/or a pull-down resistor. See the description above for
114 to be connected-ground, which usually means a pull-down resistance of
118 io-channels:
124 - compatible
125 - pullup-uv
126 - pullup-ohm
127 - pulldown-ohm
128 - io-channels
133 - |
136 io-channels = <&gpadc 0x06>;
137 pullup-uv = <1800000>;
138 pullup-ohm = <220000>;
139 pulldown-ohm = <0>;
140 #thermal-sensor-cells = <0>;