rotary encoder for embedded. Suitable for gray-code incremental encoders, complay with embedded-hal (https://docs.rs/embedded-hal/0.2.7/embedded_hal)
for arduino and stm32f401 mcus, provide interrupt sample and busy loop sample.
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rotary pins should be pull-up input, on other word, With no external circuit pulling the pin low, it will be read high.
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when finding direction is opposite as you wishing, you should switch the pin-clk, pin-dt.
rotary encoder produces are based on a 2-bit gray code available on 2 digital data signal lines. There are 4 possible combinations of on and off on these 2 signal lines, related gray code shows below:
| Position | Bit A | Bit B |
|---|---|---|
| 0 | 0 | 0 |
| 1/4 | 1 | 0 |
| 1/2 | 1 | 1 |
| 3/4 | 0 | 1 |
| 1 | 0 | 0 |
// cw:
a b c d
│ | | | │ │
──┼───┐ ┌───┼───┐ ┌───┼───┐ ┌───────┐
│ │ │ │ │ │ │ │ │ │ pin2
│ └───────┘ │ └───────┘ │ └───────┘ └────
├───────┐ ├───────┐ ├───────┐
│ │ │ │ │ │ pin1
──┤ └───────┤ └───────┤ └───────
│ │ │
// if ((old_state == 2) && (thisState == 3)) {
// knobPosition++;
// } else if ((old_state == 3) && (thisState == 1)) {
// knobPosition++;
// } else if ((old_state == 1) && (thisState == 0)){
// knobPosition++;
// } else if ((old_state == 0) && (thisState == 2)) {
// knobPosition++;
// ccw:
│ │ │
──┼───┐ ┌───┼───┐ ┌───┼───┐ ┌───────┐
│ │ │ │ │ │ │ │ │ │ pin2
│ └───────┘ │ └───────┘ │ └───────┘ └────
──┤ ┌───────┤ ┌───────┤ ┌───────┐
│ │ │ │ │ │ │ pin1
├───────┘ ├───────┘ ├───────┘ └────
│ │ │
// } else if ((old_state == 3) && (thisState == 2)) {
// knobPosition--;
// } else if ((old_state == 2) && (thisState == 0)) {
// knobPosition--;
// } else if ((old_state == 0) && (thisState == 1)) {
// knobPosition--;
// } else if ((old_state == 1) && (thisState == 3)) {
// knobPosition--;
// }
//