The Collect Data function reads the desired result registers and sends the data based on the specified settings. This function works best with continuous conversion mode and does not configure the EVM or associated register settings for you. Collect mode started and stopped via the serial COM port, however the results will be sent over the USB BULK channel. To use this mode, use the following format:

• Start collecting data format: collect timerPeriod collectFlags channelAddressIDs numDevices
  • Where collect is always lower case, and each parameter is the decimal representation of the value in the following format:
    • timerPeriod
      • The timer delay used in the MCU to allow data collection sample sets (in µs, unsigned 32bit value).
    • collectFlags
      • a byte of data that has a 1 to collect and a 0 to not collect each register value type, according to the following definitions (note to only use energy and charge flags when the device supports that, otherwise set to 0):
        • VSHUNT = 0b1000
        • VBUS = 0b0100
        • CURRENT = 0b0010
        • POWER = 0b0001
    • channelAddressIDs
      • This is the 4 LSBs of each I2C address chained together, starting with the LSBs.
        • For example, if EVM 1 is at address 0x41 and EVM 2 is on ox43, the value here would be 0b00110001
    • NumDevices
      • The number of EVMs chained together (1-4).
  • For example, to start data collection for VSHUNT and VBUS every 2.2 ms, for two INA226EVMs with EVM 1 address = 0x41 and EVM 2 address = 0x43, you would send: collect 2200 12 49 2
    • For this example, the EVM would return the acknowledgment and state in JSON format:
      • {"acknowledge":"collect 2200 12 49 2"}
      • {"evm_state":"collecting"}
  • The USB BULK channel receives data in the format: frameID deviceNumID address registerSize data
    • Where each parameter is the decimal representation of the value in the following format:
      • frameID (1 byte)
        • Always reads 0. Used to ensure data is aligned.
      • deviceNumID (1 byte)
        • An ID number corresponding to the EVM number.
          • From the above example, this will be 1 if reading from EVM 1 which had address set to 0x41, and 2 if reading from EVM 2 which had a address set to 0x43.
      • address (1 byte)
        • The register address that was read from the device.
      • registerSize (1 byte)
        • The number of bytes that the following data will have.
      • data (1 byte at a time)
        • The register data value, given in bytes with the most significant byte first.
• Stop collecting data format: stop
  • Where stop is always lower case.
  • The EVM will return the acknowledgment and state in JSON format:
    • {"acknowledge":"stop"}
    • {"evm_state":"idle"}