Created
January 14, 2020 12:58
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Potentiometer scanning snippet
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| // #include "analog.h" | |
| #include "stdio.h" | |
| #include "stdlib.h" | |
| #include "stdint.h" | |
| #include "stdbool.h" | |
| // dz+s | 98*s | s+dz | |
| // 100s+2dz = 1024 | |
| // dz = 12 | |
| // s = 10 | |
| // #s = (1024 - 2dz) / s | |
| // s = (1024 - 2dz) / #s | |
| // dz = (1024-#s*s) / 2 | |
| #define POT_STEPS 100 | |
| #define DEADZONE 12 | |
| #define HYST 1 | |
| #define POT_PIN_HIGH 0 | |
| #define POT_PIN_READ 1 | |
| #define POT_BOTTOM_KEY 0 | |
| #define POT_TOP_KEY 1 | |
| #define POT_DOWN_KEY 2 | |
| #define POT_UP_KEY 3 | |
| #define ANALOG_MAX 1023 | |
| // MOCKING | |
| uint16_t pin_value; | |
| void setPinInputHigh(uint16_t pin) {} | |
| uint16_t analogReadPin(uint16_t pin) { | |
| return pin_value; | |
| } | |
| void send_key(uint16_t key) { | |
| printf("%d", key); | |
| } | |
| int16_t min(int16_t a, int16_t b) { | |
| return a < b ? a : b; | |
| } | |
| int16_t max(int16_t a, int16_t b) { | |
| return a > b ? a : b; | |
| } | |
| // LOGIC | |
| const uint16_t step_size = ((ANALOG_MAX + 1) - 2 * DEADZONE) / POT_STEPS; | |
| const uint16_t low_dz = step_size + DEADZONE; | |
| const uint16_t high_dz = ANALOG_MAX - (step_size + DEADZONE); | |
| uint16_t last = 0; | |
| uint16_t into_range(uint16_t val) { | |
| // move value into range between deadzones | |
| // new val ranges [0, ANALOG_MAX-2*DEADZONE] | |
| val = min(val, ANALOG_MAX - DEADZONE); | |
| return max(0, val - DEADZONE); | |
| } | |
| void matrix_init(void) { | |
| setPinInputHigh(POT_PIN_HIGH); | |
| last = analogReadPin(POT_PIN_READ); | |
| printf("step_size=%d\tlow_dz=%d\thigh_dz=%d\n", step_size, low_dz, high_dz); | |
| printf("init done, last=%d\n", last); | |
| } | |
| void scan_pot(void) { | |
| uint16_t cur = analogReadPin(POT_PIN_READ); | |
| int16_t d = cur - last; | |
| printf("cur=%d\tlast=%d\n", cur, last); | |
| if (abs(d) <= HYST || (last < low_dz && cur < low_dz) || (last > high_dz && cur > high_dz)) { | |
| // change is zero, within hysteresis or within deadzone | |
| printf("no change\n"); | |
| return; | |
| } | |
| uint16_t cur1 = into_range(cur); | |
| printf("ranged cur = %d\n", into_range(cur)); | |
| // calculate step positions | |
| uint16_t cur_step = cur1 / step_size; | |
| printf("ranged last = %d\n", into_range(last)); | |
| uint16_t last_step = into_range(last) / step_size; | |
| int16_t ds = cur_step - last_step; | |
| printf("cur_step=%d\tlast_step=%d\tds=%d\n", cur_step, last_step, ds); | |
| if (ds == 0) { | |
| return; | |
| } | |
| uint16_t steps; | |
| bool max; | |
| uint16_t step_key; | |
| uint16_t max_key; | |
| if (ds > 0) { | |
| steps = ds; | |
| max = cur_step == POT_STEPS - 1; | |
| step_key = POT_UP_KEY; | |
| max_key = POT_TOP_KEY; | |
| } else { | |
| steps = -ds; | |
| max = cur_step == 0; | |
| step_key = POT_DOWN_KEY; | |
| max_key = POT_BOTTOM_KEY; | |
| } | |
| for (int i = 0; i < steps-1; ++i) | |
| { | |
| send_key(step_key); | |
| } | |
| if (max) { | |
| send_key(max_key); | |
| } else { | |
| send_key(step_key); | |
| } | |
| printf("\n"); | |
| last = cur; | |
| } | |
| int main(void) { | |
| printf("gonna do things...\n"); | |
| pin_value = 0; | |
| matrix_init(); | |
| scan_pot(); | |
| pin_value = 100; | |
| scan_pot(); | |
| pin_value = 200; | |
| scan_pot(); | |
| pin_value = 200; | |
| scan_pot(); | |
| pin_value = 201; | |
| scan_pot(); | |
| pin_value = 202; | |
| scan_pot(); | |
| pin_value = 203; | |
| scan_pot(); | |
| pin_value = 1023; | |
| scan_pot(); | |
| pin_value = 0; | |
| scan_pot(); | |
| } |
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