NAME

    Device::Chip::nRF24L01P - chip driver for a nRF24L01+

DESCRIPTION

    This Device::Chip subclass provides specific communication to a Nordic
    Semiconductor nRF24L01+ chip attached to a computer via an SPI adapter.

    The reader is presumed to be familiar with the general operation of
    this chip; the documentation here will not attempt to explain or define
    chip-specific concepts or features, only the use of this module to
    access them.

MOUNT PARAMETERS

 ce

    The name of the GPIO line on the adapter that is connected to the Chip
    Enable (CE) pin. This module defaults to using the AUX line on a Bus
    Pirate, or D4 on an FTDI FT232H; for other adapter types the parameter
    will have to be supplied.

METHODS

 clear_caches

       $nrf->clear_caches

    The chip object stores a cache of the register values it last read or
    wrote, so it can optimise updates of configuration. This method clears
    these caches, ensuring a fresh SPI transfer next time the register
    needs to be read.

    This should not normally be necessary, other than for debugging.

 latest_status

       $status = $nrf->latest_status

    Returns the latest cached copy of the status register from the most
    recent SPI interaction. As this method does not perform any IO, it
    returns its result immediately rather than via a Future.

    Returns a HASH reference containing the following boolean fields

     RX_DR TX_DS MAX_RT TX_FULL

    Also returned is a field called RX_P_NO, which is either a pipe number
    (0 to 5) or undef.

 reset_interrupt

       $nrf->reset_interrupt->get

    Clears the interrupt flags in the STATUS register.

 read_status

       $status = $nrf->read_status->get

    Reads and returns the current content of the status register as a HASH
    reference as per latest_status.

 read_config

       $config = $nrf->read_config->get

 change_config

       $nrf->change_config( %config )->get

    Reads or writes the chip-wide configuration. This is an amalgamation of
    all the non-pipe-specific configuration registers; CONFIG, SETUP_AW,
    SETUP_RETR, RF_CH, RF_SETUP, TX_ADDR and FEATURE.

    When reading, the fields are returned in a HASH reference whose names
    are the original bitfield names found in the Nordic Semiconductor data
    sheet. When writing, these fields are accepted as named parameters to
    the change_config method directly.

    Some of the fields have special processing for convenience. They are:

      * CRCO

      Gives the CRC length in bytes, as either 1 or 2.

      * AW

      Gives the full address width in bytes, between 3 and 5.

      * ARD

      Gives the auto retransmit delay in microseconds directly; a multiple
      of 250 between 250 and 4000.

      * RF_DR

      Gives the RF data rate in bytes/sec; omits the RF_DR_LOW and
      RF_DR_HIGH fields; as 250000, 1000000 or 2000000

      * RF_PWR

      Gives the RF output power in dBm directly, as -18, -12, -6 or 0.

      * TX_ADDR

      Gives the PTX address as a string of 5 capital hexadecimal encoded
      octets, separated by colons.

    Whenever the config is read it is cached within the $chip instance.
    Whenever it is written, any missing fields in the passed configuration
    are pre-filled by the cached config, and only those registers that need
    writing will be written.

 read_rx_config

       $config = $nrf->read_rx_config( $pipeno )->get

 change_rx_config

       $nrf->change_rx_config( $pipeno, %config )->get

    Reads or writes the per-pipe RX configuration. This is composed of the
    per-pipe bits of the EN_AA and EN_RXADDR registers and its RX_ADDR_Pn
    register.

    Addresses are given as a string of 5 octets in capitalised hexadecimal
    notation, separated by colons.

    When reading an address from pipes 2 to 5, the address of pipe 1 is
    used to build a complete address string to return. When writing and
    address to these pipes, all but the final byte is ignored.

 observe_tx_counts

       $counts = $nrf->observe_tx_counts->get

    Reads the OBSERVE_TX register and returns the two counts from it.

 rpd

       $rpd = $nrf->rpd->get

    Reads the RPD register

 fifo_status

       $status = $nrf->fifo_status->get

    Reads the FIFO_STATUS register and returns the five bit fields from it.

 pwr_up

       $nrf->pwr_up( $pwr )->get

    A convenient shortcut to setting the PWR_UP configuration bit.

 chip_enable

       $nrf->chip_enable( $ce )->get

    Controls the Chip Enable (CE) pin of the chip.

 read_rx_payload_width

       $len = $nrf->read_rx_payload_width->get

    Returns the width of the most recently received payload, when in DPL
    mode. Remember that DPL needs to be enabled (using EN_DPL) on both the
    transmitter and receiver before this will work.

 read_rx_payload

       $data = $nrf->read_rx_payload( $len )->get

    Reads the most recently received RX FIFO payload buffer.

 write_tx_payload

       $nrf->write_tx_payload( $data, %opts )->get

    Writes the next TX FIFO payload buffer. Takes the following options:

    no_ack => BOOL

      If true, uses the W_TX_PAYLOAD_NO_ACK command, requesting that this
      payload does not requre auto-ACK.

 flush_rx_fifo

       $nrf->flush_rx_fifo->get

 flush_tx_fifo

       $nrf->flush_tx_fifo->get

    Flush the RX or TX FIFOs, discarding all their contents.

AUTHOR

    Paul Evans <leonerd@leonerd.org.uk>

