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maxim,max31865 (on spi bus)

Vendor: Maxim Integrated Products

Description

Maxim MAX31865 SPI RTD-to-Digital Converter Temperature Sensor.
Find the datasheet here:
https://datasheets.maximintegrated.com/en/ds/MAX31865.pdf

Properties

Properties not inherited from the base binding file.

Name

Type

Details

friendly-name

string

 
Human readable string describing the sensor. It can be used to
distinguish multiple instances of the same model (e.g., lid accelerometer
vs. base accelerometer in a laptop) to a host operating system.

This property is defined in the Generic Sensor Property Usages of the HID
Usage Tables specification
(https://usb.org/sites/default/files/hut1_3_0.pdf, section 22.5).

supply-gpios

phandle-array

 
GPIO specifier that controls power to the device.

This property should be provided when the device has a dedicated
switch that controls power to the device.  The supply state is
entirely the responsibility of the device driver.

Contrast with vin-supply.

vin-supply

phandle

 
Reference to the regulator that controls power to the device.
The referenced devicetree node must have a regulator compatible.

This property should be provided when device power is supplied
by a shared regulator.  The supply state is dependent on the
request status of all devices fed by the regulator.

Contrast with supply-gpios.  If both properties are provided
then the regulator must be requested before the supply GPIOS is
set to an active state, and the supply GPIOS must be set to an
inactive state before releasing the regulator.

spi-max-frequency

int

 
Maximum clock frequency of device's SPI interface in Hz

This property is required.

duplex

int

 
Duplex mode, full or half. By default it's always full duplex thus 0
as this is, by far, the most common mode.
Use the macros not the actual enum value, here is the concordance
list (see dt-bindings/spi/spi.h)
  0    SPI_FULL_DUPLEX
  2048 SPI_HALF_DUPLEX

Legal values: 0, 2048

frame-format

int

 
Motorola or TI frame format. By default it's always Motorola's,
thus 0 as this is, by far, the most common format.
Use the macros not the actual enum value, here is the concordance
list (see dt-bindings/spi/spi.h)
  0     SPI_FRAME_FORMAT_MOTOROLA
  32768 SPI_FRAME_FORMAT_TI

Legal values: 0, 32768

spi-cpol

boolean

 
SPI clock polarity which indicates the clock idle state.
If it is used, the clock idle state is logic high; otherwise, low.

spi-cpha

boolean

 
SPI clock phase that indicates on which edge data is sampled.
If it is used, data is sampled on the second edge; otherwise, on the first edge.

spi-hold-cs

boolean

 
In some cases, it is necessary for the master to manage SPI chip select
under software control, so that multiple spi transactions can be performed
without releasing it. A typical use case is variable length SPI packets
where the first spi transaction reads the length and the second spi transaction
reads length bytes.

resistance-at-zero

int

 
Sensor resistance in ohms at 0 Celsius (100 ohms for PT100, 1000 ohms for PT1000)

This property is required.

resistance-reference

int

 
Circuit reference resistance in ohms (recommended on MAX31865 datasheet 400 ohms for PT100, 4000 ohms for PT1000, the Adafruit boards use 430 ohms and 4300 ohms)

This property is required.

low-threshold

int

 
Low fault threshold (ADC CODE, 15-bit value, unit-free, default value is the minimum value)

high-threshold

int

 
High fault threshold (ADC CODE, 15-bit value, unit-free, default value is the maximum value)

Default value: 32767

maxim,3-wire

boolean

 
3-wire enabled (@a true) or 2-wire/4-wire (@a false)

filter-50hz

boolean

 
50 Hz filter enabled (@a true) or 60 Hz filter enabled (@a false)