gobot.io/x/gobot@v1.16.0/drivers/spi/mcp3002.go (about)

     1  package spi
     2  
     3  import (
     4  	"errors"
     5  	"strconv"
     6  
     7  	"gobot.io/x/gobot"
     8  )
     9  
    10  // MCP3002DriverMaxChannel is the number of channels of this A/D converter.
    11  const MCP3002DriverMaxChannel = 2
    12  
    13  // MCP3002Driver is a driver for the MCP3002 A/D converter.
    14  type MCP3002Driver struct {
    15  	name       string
    16  	connector  Connector
    17  	connection Connection
    18  	Config
    19  	gobot.Commander
    20  }
    21  
    22  // NewMCP3002Driver creates a new Gobot Driver for MCP3002 A/D converter
    23  //
    24  // Params:
    25  //      a *Adaptor - the Adaptor to use with this Driver
    26  //
    27  // Optional params:
    28  //      spi.WithBus(int):    	bus to use with this driver
    29  //     	spi.WithChip(int):    	chip to use with this driver
    30  //      spi.WithMode(int):    	mode to use with this driver
    31  //      spi.WithBits(int):    	number of bits to use with this driver
    32  //      spi.WithSpeed(int64):   speed in Hz to use with this driver
    33  //
    34  func NewMCP3002Driver(a Connector, options ...func(Config)) *MCP3002Driver {
    35  	d := &MCP3002Driver{
    36  		name:      gobot.DefaultName("MCP3002"),
    37  		connector: a,
    38  		Config:    NewConfig(),
    39  	}
    40  	for _, option := range options {
    41  		option(d)
    42  	}
    43  	return d
    44  }
    45  
    46  // Name returns the name of the device.
    47  func (d *MCP3002Driver) Name() string { return d.name }
    48  
    49  // SetName sets the name of the device.
    50  func (d *MCP3002Driver) SetName(n string) { d.name = n }
    51  
    52  // Connection returns the Connection of the device.
    53  func (d *MCP3002Driver) Connection() gobot.Connection { return d.connection.(gobot.Connection) }
    54  
    55  // Start initializes the driver.
    56  func (d *MCP3002Driver) Start() (err error) {
    57  	bus := d.GetBusOrDefault(d.connector.GetSpiDefaultBus())
    58  	chip := d.GetChipOrDefault(d.connector.GetSpiDefaultChip())
    59  	mode := d.GetModeOrDefault(d.connector.GetSpiDefaultMode())
    60  	bits := d.GetBitsOrDefault(d.connector.GetSpiDefaultBits())
    61  	maxSpeed := d.GetSpeedOrDefault(d.connector.GetSpiDefaultMaxSpeed())
    62  
    63  	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
    64  	if err != nil {
    65  		return err
    66  	}
    67  	return nil
    68  }
    69  
    70  // Halt stops the driver.
    71  func (d *MCP3002Driver) Halt() (err error) {
    72  	return
    73  }
    74  
    75  // Read reads the current analog data for the desired channel.
    76  func (d *MCP3002Driver) Read(channel int) (result int, err error) {
    77  	if channel < 0 || channel > MCP3002DriverMaxChannel-1 {
    78  		return 0, errors.New("Invalid channel for read")
    79  	}
    80  
    81  	tx := make([]byte, 2)
    82  	tx[0] = 0x68 + (byte(channel) << 4)
    83  	tx[1] = 0x00
    84  
    85  	rx := make([]byte, 2)
    86  
    87  	err = d.connection.Tx(tx, rx)
    88  	if err == nil && len(rx) == 2 {
    89  		result = int((rx[0]&0x3))<<8 + int(rx[2])
    90  	}
    91  
    92  	return result, err
    93  }
    94  
    95  // AnalogRead returns value from analog reading of specified pin
    96  func (d *MCP3002Driver) AnalogRead(pin string) (value int, err error) {
    97  	channel, _ := strconv.Atoi(pin)
    98  	value, err = d.Read(channel)
    99  
   100  	return
   101  }