90 lines
2.3 KiB
Go
90 lines
2.3 KiB
Go
package spi
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import (
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"image/color"
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"math"
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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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*Driver
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vals []color.RGBA
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brightness uint8
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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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//
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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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// bright - the default brightness to apply for all LEDs (must be between 0 and 31).
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//
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// Optional params:
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//
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// spi.WithBusNumber(int): bus to use with this driver.
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// spi.WithChipNumber(int): chip to use with this driver.
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// spi.WithMode(int): mode to use with this driver.
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// spi.WithBitCount(int): number of bits to use with this driver.
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// spi.WithSpeed(int64): speed in Hz to use with this driver.
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func NewAPA102Driver(a Connector, count int, bright uint8, options ...func(Config)) *APA102Driver {
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d := &APA102Driver{
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Driver: NewDriver(a, "APA102"),
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vals: make([]color.RGBA, count),
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brightness: uint8(math.Min(float64(bright), 31)),
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}
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for _, option := range options {
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option(d)
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}
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return d
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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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// SetBrightness sets the ith LED's brightness to the given value.
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// Must be between 0 and 31.
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func (d *APA102Driver) SetBrightness(i uint8) {
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d.brightness = uint8(math.Min(float64(i), 31))
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}
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// Brightness return driver brightness value.
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func (d *APA102Driver) Brightness() uint8 {
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return d.brightness
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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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if c.A != 0 {
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tx[j] = 0xe0 + byte(math.Min(float64(c.A), 31))
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} else {
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tx[j] = 0xe0 + d.brightness
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}
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tx[j+1] = c.B
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tx[j+2] = c.G
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tx[j+3] = 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.WriteBytes(tx)
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}
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