GY-63_MS5611/libraries/I2C_SCANNER

I2C_SCANNER

Arduino class to implement an I2C scanner.

Description

I2C_SCANNER is a class to build an I2C scanner, either minimal or more complex.

The class provides different functions to analyse the connectivity of devices on the I2C bus. There are functions to adjust the frequency and functions to select the bus in case of multiple I2C ports.

Furthermore there are different functions to scan the I2C port, see the section scanning below.

If there is missing functionality, please file an issue.

Interface

Constructor

• I2C_SCANNER(TwoWire *wire = &Wire) Constructor with the default Wire I2C bus.
• bool begin() To start the Wire library.
• bool begin(int sda, int scl) idem for ESP32 et al.

Configuration

• bool setClock(uint32_t clockFrequency = 100000UL) sets the speed of the I2C bus. Returns true.
• uint32_t getClock() supported by some platforms, including ESP32.
• uint8_t getWireCount() returns the number of Wire ports (hardware I2C).
• bool setWire(TwoWire *wire = &Wire) set a Wire port by 'name' e.g. Wire1.
• bool setWire(uint8_t n) sets the Wire port by number.
• TwoWire * getWire() returns the Wire object set.

Scanning

• bool ping(uint8_t address) Tries to make contact with I2C address. Returns true on success.
• int diag(uint8_t address) Tries to make contact with I2C address. Returns Wire status code 0 == OK, others might depend on platform used.
• int32_t pingTime(uint8_t address) Tries to make contact with I2C address. Returns time used in micros. Returns minus time (<0) if failed to contact.
• uint8_t count(uint8_t start = 0, uint8_t end = 127) pings address range. Includes start and end address too. Returns the number of addresses found.

Reset

(needs testing)

• int softwareReset(uint8_t method = 0) sends a I2C SWRST command over the configured I2C bus. This will cause all devices that support this command to do a "power on" reset. The code implements two methods,
  • 0 = NXP spec (default)
  • 1 = from PCA9634 issue.

The softwareReset() function should return 0 for success. The value -999 indicates invalid method selected. Other are I2C specific error codes.

Operation

See examples.

Future ideas

Should

• add examples.
• documentation.
• add setWireTimeOut(uint32_t timeout, bool reset_with_timeout = true)
  • portable? clear? reset?

Could

• add bool hardwareReset()
  • keep data HIGH for X clock pulses - google this.
  • (needs investigation)
• implement getClock() for AVR based platforms
  • reverse calculate TWBR and prescaler.
  • (needs investigation)

Won't

• device analysis
  • add bool send(address, uint8_t *buffer, uint8_t length)
  • add bool receive(address, uint8_t *buffer, uint8_t length)
• add iterator
  • uint8_t first(uint8_t start = 0) returns address or 255
  • uint8_t next() returns address or 255.
• uint8_t _devices[16] cache hits ?
  • No
• implement a SW_I2C
  • No, user may use a SW_I2C that derives from TwoWire.