7 セグメントディスプレイ

ピンを開く

{:ok, sdi} = Circuits.GPIO.open("GPIO17", :output)
{:ok, rclk} = Circuits.GPIO.open("GPIO18", :output)
{:ok, srclk} = Circuits.GPIO.open("GPIO27", :output)

2進数をビットに分割する

import Bitwise

0b10100001 |> inspect(base: :binary)

0b10100001 <<< 1 |> inspect(base: :binary)

0b10100001 <<< 2 |> inspect(base: :binary)

0b10100001 <<< 3 |> inspect(base: :binary)

(0b10100001 <<< 0 &amp;&amp;&amp; 0b10000000) |> IO.inspect(base: :binary)
(0b10100001 <<< 1 &amp;&amp;&amp; 0b10000000) |> IO.inspect(base: :binary)
(0b10100001 <<< 2 &amp;&amp;&amp; 0b10000000) |> IO.inspect(base: :binary)
(0b10100001 <<< 3 &amp;&amp;&amp; 0b10000000) |> IO.inspect(base: :binary)
(0b10100001 <<< 4 &amp;&amp;&amp; 0b10000000) |> IO.inspect(base: :binary)
(0b10100001 <<< 5 &amp;&amp;&amp; 0b10000000) |> IO.inspect(base: :binary)
(0b10100001 <<< 6 &amp;&amp;&amp; 0b10000000) |> IO.inspect(base: :binary)
(0b10100001 <<< 7 &amp;&amp;&amp; 0b10000000) |> IO.inspect(base: :binary)

data = 0b10100001

for bit <- 0..7 do
  div(data <<< bit &amp;&amp;&amp; 0x80, 128)
end

74HC595 に並列出力を設定する

shift_out = fn data, sdi, rclk, srclk ->
  for bit <- 0..7 do
    bit = data <<< bit &amp;&amp;&amp; 0x80
    Circuits.GPIO.write(sdi, bit)
    Circuits.GPIO.write(srclk, 1)
    Process.sleep(1)
    Circuits.GPIO.write(srclk, 0)
  end

  Circuits.GPIO.write(rclk, 1)
  Process.sleep(1)
  Circuits.GPIO.write(rclk, 0)
end

shift_out.(0b00111111, sdi, rclk, srclk)

16 進数を表示する

seg_code = [
  0x3F,
  0x06,
  0x5B,
  0x4F,
  0x66,
  0x6D,
  0x7D,
  0x07,
  0x7F,
  0x6F,
  0x77,
  0x7C,
  0x39,
  0x5E,
  0x79,
  0x71
]

seg_code
|> Enum.map(fn code ->
  shift_out.(code, sdi, rclk, srclk)
  Process.sleep(500)
end)

HELLO. を表示する

elixir_code = [
  0b01110110,
  0b01111001,
  0b00111000,
  0b00111000,
  0b00111111,
  0b10000000
]

elixir_code
|> Enum.map(fn code ->
  shift_out.(code, sdi, rclk, srclk)
  Process.sleep(500)
  shift_out.(0b00000000, sdi, rclk, srclk)
  Process.sleep(200)
end)

ピンを閉じる

Circuits.GPIO.close(sdi)
Circuits.GPIO.close(rclk)
Circuits.GPIO.close(srclk)