93 lines
2.2 KiB
Go
93 lines
2.2 KiB
Go
package spi
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import (
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"image/color"
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"gobot.io/x/gobot"
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)
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// APA102Driver is a driver for the APA102 programmable RGB LEDs
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type APA102Driver struct {
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name string
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connector Connector
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connection Connection
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vals []color.RGBA
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}
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// NewAPA102Driver creates a new Gobot Driver for APA102 RGB LEDs.
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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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// count int - how many LEDs are in the array controlled by this driver
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//
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func NewAPA102Driver(a Connector, count int) *APA102Driver {
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d := &APA102Driver{
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name: gobot.DefaultName("APA102"),
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connector: a,
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vals: make([]color.RGBA, count),
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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 *APA102Driver) Name() string { return d.name }
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// SetName sets the name of the device.
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func (d *APA102Driver) SetName(n string) { d.name = n }
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// Connection returns the Connection of the device.
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func (d *APA102Driver) Connection() gobot.Connection { return d.connection.(gobot.Connection) }
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// Start initializes the driver.
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func (d *APA102Driver) 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 *APA102Driver) Halt() (err error) {
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d.connection.Close()
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return
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}
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// SetRGBA sets the ith LED's color to the given RGBA value.
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// A subsequent call to Draw is required to transmit values
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// to the LED strip.
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func (d *APA102Driver) SetRGBA(i int, v color.RGBA) {
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d.vals[i] = v
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}
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// Draw displays the RGBA values set on the actual LED strip.
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func (d *APA102Driver) Draw() error {
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// TODO(jbd): dotstar allows other RGBA alignments, support those layouts.
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n := len(d.vals)
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tx := make([]byte, 4*(n+1)+(n/2+1))
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tx[0] = 0x00
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tx[1] = 0x00
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tx[2] = 0x00
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tx[3] = 0x00
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for i, c := range d.vals {
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j := (i + 1) * 4
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tx[j] = 0xe0 + byte(c.R)
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tx[j+1] = byte(c.B)
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tx[j+2] = byte(c.G)
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tx[j+3] = byte(c.R)
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}
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// end frame with at least n/2 0xff vals
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for i := (n + 1) * 4; i < len(tx); i++ {
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tx[i] = 0xff
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}
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return d.connection.Tx(tx, nil)
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}
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