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gpiostream: Implement LSB and MSB variations. (#188)

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Make the encoding clear via examples.

Comment that the non-marked version is deprecated and will be removed in the
next major version.
pull/1/head
M-A 9 years ago committed by GitHub
parent f015c64bb3
commit 11522179a3
2 changed files with 21 additions and 22 deletions
Show Stats Download Patch File Download Diff File

19
experimental/devices/nrzled/nrzled.go
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@ -16,9 +16,9 @@ import (
"periph.io/x/periph/devices"
)
// NRZ converts a byte into the Non-Return-to-Zero encoded 24 bits.
// NRZ converts a byte into the MSB-first Non-Return-to-Zero encoded 24 bits.
//
// The upper 8 bits are zeros.
// The upper 8 bits are zeros and shall be ignored.
//
// The Non-return-to-zero protocol is a self-clocking signal that enables
// one-way communication without the need of a dedicated clock signal, unlike
@ -45,9 +45,9 @@ func NRZ(b byte) uint32 {
type Dev struct {
p gpiostream.PinOut
numPixels int
channels int // Number of channels per pixel
b gpiostream.BitStream // NRZ encoded bits; cached to reduce heap fragmentation
buf []byte // Double buffer of RGB/RGBW pixels; enables partial Draw()
channels int // Number of channels per pixel
b gpiostream.BitStreamMSB // NRZ encoded bits; cached to reduce heap fragmentation
buf []byte // Double buffer of RGB/RGBW pixels; enables partial Draw()
}
func (d *Dev) String() string {
@ -166,23 +166,21 @@ func New(p gpiostream.PinOut, numPixels, hz int, channels int) (*Dev, error) {
if channels != 3 && channels != 4 {
return nil, errors.New("nrzled: specify valid number of channels (3 or 4)")
}
// It is more space effective to use gpiostream.Bits than
// gpiostream.EdgeStream.
return &Dev{
p: p,
numPixels: numPixels,
channels: channels,
b: gpiostream.BitStream{
b: gpiostream.BitStreamMSB{
Res: time.Second / time.Duration(hz),
// Each bit is encoded on 3 bits.
Bits: make(gpiostream.Bits, numPixels*3*channels),
Bits: make(gpiostream.BitsMSB, numPixels*3*channels),
},
}, nil
}
//
// raster converts a RGB/RGBW input stream into a binary output stream as it
// raster converts a RGB/RGBW input stream into a MSB binary output stream as it
// must be sent over the GPIO pin.
//
// `in` is RGB 24 bits or RGBW 32 bits. Each bit is encoded over 3 bits so the
@ -211,6 +209,7 @@ func raster(out, in []byte, outChannels, inChannels int) {
}
}
// put writes the byte v as an MSB-first NRZ encoded triplet byte into out.
func put(out []byte, v byte) {
w := NRZ(v)
out[0] = byte(w >> 16)

24
experimental/devices/nrzled/nrzled_test.go
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@ -47,8 +47,8 @@ func TestNew_3(t *testing.T) {
g := gpiostreamtest.PinOutPlayback{
N: "Yo",
Ops: []gpiostream.Stream{
&gpiostream.BitStream{
Bits: gpiostream.Bits{
&gpiostream.BitStreamMSB{
Bits: gpiostream.BitsMSB{
0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92,
0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49,
0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24,
@ -94,8 +94,8 @@ func TestNew_fail(t *testing.T) {
func TestDraw_NRGBA_3(t *testing.T) {
g := gpiostreamtest.PinOutPlayback{
Ops: []gpiostream.Stream{
&gpiostream.BitStream{
Bits: gpiostream.Bits{
&gpiostream.BitStreamMSB{
Bits: gpiostream.BitsMSB{
0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0xdb,
0x6d, 0xb6, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49,
0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24,
@ -119,8 +119,8 @@ func TestDraw_NRGBA_3(t *testing.T) {
func TestDraw_RGBA_3(t *testing.T) {
g := gpiostreamtest.PinOutPlayback{
Ops: []gpiostream.Stream{
&gpiostream.BitStream{
Bits: gpiostream.Bits{
&gpiostream.BitStreamMSB{
Bits: gpiostream.BitsMSB{
0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0xdb,
0x6d, 0xb6, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49,
0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24,
@ -144,8 +144,8 @@ func TestDraw_RGBA_3(t *testing.T) {
func TestDraw_RGBA_4(t *testing.T) {
g := gpiostreamtest.PinOutPlayback{
Ops: []gpiostream.Stream{
&gpiostream.BitStream{
Bits: gpiostream.Bits{
&gpiostream.BitStreamMSB{
Bits: gpiostream.BitsMSB{
0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92,
0x49, 0x24, 0xdb, 0x6d, 0xb6, 0xdb, 0x6d, 0xb6, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49,
0x24, 0xdb, 0x6d, 0xb6, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0xdb, 0x6d, 0xb6,
@ -171,8 +171,8 @@ func TestDraw_RGBA_4(t *testing.T) {
func TestDraw_Limits(t *testing.T) {
g := gpiostreamtest.PinOutPlayback{
Ops: []gpiostream.Stream{
&gpiostream.BitStream{
Bits: gpiostream.Bits{
&gpiostream.BitStreamMSB{
Bits: gpiostream.BitsMSB{
0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0xdb,
0x6d, 0xb6, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49,
0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24,
@ -196,8 +196,8 @@ func TestDraw_Limits(t *testing.T) {
func TestWrite_3(t *testing.T) {
g := gpiostreamtest.PinOutPlayback{
Ops: []gpiostream.Stream{
&gpiostream.BitStream{
Bits: gpiostream.Bits{
&gpiostream.BitStreamMSB{
Bits: gpiostream.BitsMSB{
0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0xdb,
0x6d, 0xb6, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49,
0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0xdb, 0x6d, 0xb6, 0x92, 0x49, 0x24, 0x92, 0x49, 0x24,

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