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111 lines
3.8 KiB
Markdown
111 lines
3.8 KiB
Markdown
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[](https://github.com/marketplace/actions/arduino_ci)
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[](https://github.com/RobTillaart/I2C_SCANNER/actions/workflows/arduino-lint.yml)
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[](https://github.com/RobTillaart/I2C_SCANNER/actions/workflows/jsoncheck.yml)
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[](https://github.com/RobTillaart/I2C_SCANNER/blob/master/LICENSE)
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[](https://github.com/RobTillaart/I2C_SCANNER/releases)
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# I2C_SCANNER
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Arduino class to implement an I2C scanner.
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## Description
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I2C_SCANNER is a class to build an I2C scanner, either minimal or more complex.
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The class provides different functions to analyse the connectivity of devices
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on the I2C bus. There are functions to adjust the frequency and functions to
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select the bus in case of multiple I2C ports.
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Furthermore there are different functions to scan the I2C port,
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see the section scanning below.
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If there is missing functionality, please file an issue.
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## Interface
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### Constructor
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- **I2C_SCANNER(TwoWire \*wire = &Wire)** Constructor with the default Wire I2C bus.
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- **bool begin()** To start the Wire library.
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- **bool begin(int sda, int scl)** idem for ESP32 et al.
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### Configuration
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- **bool setClock(uint32_t clockFrequency = 100000UL)** sets the speed of the I2C bus.
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Returns true.
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- **uint32_t getClock()** supported by some platforms, including ESP32.
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- **uint8_t getWireCount()** returns the number of Wire ports (hardware I2C).
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- **bool setWire(TwoWire \*wire = &Wire)** set a Wire port by 'name' e.g. Wire1.
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- **bool setWire(uint8_t n)** sets the Wire port by number.
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- **TwoWire \* getWire()** returns the Wire object set.
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### Scanning
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- **bool ping(uint8_t address)** Tries to make contact with I2C address.
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Returns true on success.
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- **int diag(uint8_t address)** Tries to make contact with I2C address.
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Returns Wire status code 0 == OK, others might depend on platform used.
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- **int32_t pingTime(uint8_t address)** Tries to make contact with I2C address.
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Returns time used in micros. Returns minus time (<0) if failed to contact.
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- **uint8_t count(uint8_t start = 0, uint8_t end = 127)** pings address range.
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Includes start and end address too. Returns the number of addresses found.
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### Reset
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(needs testing)
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- **int softwareReset(uint8_t method = 0)** sends a I2C SWRST command over the configured I2C bus.
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This will cause all devices that support this command to do a "power on" reset.
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The code implements two methods,
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- 0 = NXP spec (default)
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- 1 = from PCA9634 issue.
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The **softwareReset()** function should return 0 for success.
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The value -999 indicates invalid method selected.
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Other are I2C specific error codes.
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## Operation
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See examples.
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## Future ideas
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#### Should
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- add examples.
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- documentation.
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- add **setWireTimeOut(uint32_t timeout, bool reset_with_timeout = true)**
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- portable? clear? reset?
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#### Could
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- add **bool hardwareReset()**
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- keep data HIGH for X clock pulses - google this.
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- (needs investigation)
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- implement **getClock()** for AVR based platforms
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- reverse calculate TWBR and prescaler.
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- (needs investigation)
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#### Won't
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- device analysis
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- add **bool send(address, uint8_t \*buffer, uint8_t length)**
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- add **bool receive(address, uint8_t \*buffer, uint8_t length)**
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- add iterator
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- **uint8_t first(uint8_t start = 0)** returns address or 255
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- **uint8_t next()** returns address or 255.
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- **uint8_t \_devices[16]** cache hits ?
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- No
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- implement a SW_I2C
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- No, user may use a SW_I2C that derives from TwoWire. |