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88 lines
2.1 KiB
Go
88 lines
2.1 KiB
Go
package spi
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import (
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"errors"
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"strconv"
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"gobot.io/x/gobot"
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)
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// MCP3008DriverMaxChannel is the number of channels (plus one) of this A/D converter.
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const MCP3008DriverMaxChannel = 7
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// MCP3008Driver is a driver for the MCP3008 A/D converter.
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type MCP3008Driver struct {
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name string
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connector Connector
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connection Connection
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}
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// NewMCP3008Driver creates a new Gobot Driver for MCP3008Driver A/D converter
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//
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// Params:
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// a *Adaptor - the Adaptor to use with this Driver
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//
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func NewMCP3008Driver(a Connector) *MCP3008Driver {
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d := &MCP3008Driver{
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name: gobot.DefaultName("MCP3008"),
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connector: a,
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}
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return d
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}
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// Name returns the name of the device.
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func (d *MCP3008Driver) Name() string { return d.name }
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// SetName sets the name of the device.
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func (d *MCP3008Driver) SetName(n string) { d.name = n }
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// Connection returns the Connection of the device.
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func (d *MCP3008Driver) Connection() gobot.Connection { return d.connection.(gobot.Connection) }
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// Start initializes the driver.
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func (d *MCP3008Driver) Start() (err error) {
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bus := d.connector.GetSpiDefaultBus()
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mode := d.connector.GetSpiDefaultMode()
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maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
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d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
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if err != nil {
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return err
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}
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return nil
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}
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// Halt stops the driver.
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func (d *MCP3008Driver) Halt() (err error) {
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d.connection.Close()
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return
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}
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// Read reads the current analog data for the desired channel.
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func (d *MCP3008Driver) Read(channel int) (result int, err error) {
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if channel < 0 || channel > MCP3008DriverMaxChannel {
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return 0, errors.New("Invalid channel for read")
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}
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tx := make([]byte, 3)
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tx[0] = 0x01
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tx[1] = 0x80 + (byte(channel) << 4)
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tx[2] = 0x00
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rx := make([]byte, 3)
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err = d.connection.Tx(tx, rx)
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if err == nil && len(rx) == 3 {
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result = int(((rx[1] & 0x03) << 8) + rx[2])
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}
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return result, err
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}
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// AnalogRead returns value from analog reading of specified pin
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func (d *MCP3008Driver) AnalogRead(pin string) (value int, err error) {
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channel, _ := strconv.Atoi(pin)
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value, err = d.Read(channel)
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return
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}
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