avsa242 / si70xx-spin

Parallax P8X32A/Propeller driver object for Si70xx combination Temperature/Relative Humidity sensors

si70xx-spin

---

This is a P8X32A/Propeller, P2X8C4M64P/Propeller 2 driver object for Silicon Labs Si70xx series temperature/humidity sensors.

IMPORTANT: This software is meant to be used with the spin-standard-library (P8X32A) or p2-spin-standard-library (P2X8C4M64P). Please install the applicable library first before attempting to use this code, otherwise you will be missing several files required to build the project.

Salient Features

• I2C Connection up to 400kHz
• Temperature in hundredths of a degree (scale can be set to Fahrenheit or Celsius)
• Relative humidity in hundredths of a percent
• On-chip heater control: enable/disable, set drive strength/current level
• Set sensor resolution, in bits
• Read chip-specific info: device ID/part number, firmware rev, 64-bit serial number

Requirements

P1/SPIN1:

• spin-standard-library
• 1 extra core/cog for the PASM I2C engine (none if bytecode-based I2C engine is used)
• sensor.temp_rh.common.spinh (source: spin-standard-library)

P2/SPIN2:

• p2-spin-standard-library
• sensor.temp_rh.common.spin2h (source: p2-spin-standard-library)

Compiler Compatibility

Processor	Language	Compiler	Backend	Status
P1	SPIN1	FlexSpin (5.9.14-beta)	Bytecode	OK
P1	SPIN1	FlexSpin (5.9.14-beta)	Native code	OK
P1	SPIN1	OpenSpin (1.00.81)	Bytecode	Untested (deprecated)
P2	SPIN2	FlexSpin (5.9.14-beta)	NuCode	FTBFS
P2	SPIN2	FlexSpin (5.9.14-beta)	Native code	OK
P1	SPIN1	Brad's Spin Tool (any)	Bytecode	Unsupported
P1, P2	SPIN1, 2	Propeller Tool (any)	Bytecode	Unsupported
P1, P2	SPIN1, 2	PNut (any)	Bytecode	Unsupported

Limitations

• TBD

si70xx-spin's Issues

Add support for CRC checks

The sensor sends CRC bytes to the host along with the data. Add runtime (optional) support for checking the data and comparing our own CRC to that sent by the sensor.