120 lines
2.6 KiB
C
120 lines
2.6 KiB
C
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#include "wokwi-api.h"
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#include <stdio.h>
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#include <stdlib.h>
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/* -------------------------------------------------- */
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/* States */
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typedef enum { STATE_NORMAL, STATE_RISING, STATE_FALLING } hr_state_t;
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typedef enum { STATE_SLOW = 0, STATE_FAST = 1 } hr_speed_t;
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/* -------------------------------------------------- */
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/* Chip state */
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typedef struct {
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pin_t out_pin;
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pin_t btn_pin;
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float bpm;
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int last_target;
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hr_state_t state;
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hr_speed_t speed;
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int pulseValue;
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timer_t update_timer;
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} chip_state_t;
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/* -------------------------------------------------- */
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/* Output mapping */
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static void update_output_voltage(chip_state_t *chip) {
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float volts = (chip->bpm * 3.3f) / 675.0f;
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if (volts < 0.0f)
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volts = 0.0f;
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if (volts > 3.3f)
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volts = 3.3f;
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pin_dac_write(chip->out_pin, volts);
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printf("BPM: %.1f | Voltage: %.3fV\n", chip->bpm, volts);
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}
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/* -------------------------------------------------- */
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/* Main update loop */
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static void update_cb(void *user_data) {
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chip_state_t *chip = user_data;
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int target = attr_read(chip->pulseValue);
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/* Read pull-down switch: LOW=SLOW, HIGH=FAST */
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chip->speed = pin_read(chip->btn_pin) ? STATE_FAST : STATE_SLOW;
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/* Detect target change and re-evaluate direction */
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if (target != chip->last_target) {
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if (chip->bpm < target) {
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chip->state = STATE_RISING;
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} else if (chip->bpm > target) {
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chip->state = STATE_FALLING;
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} else {
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chip->state = STATE_NORMAL;
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}
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chip->last_target = target;
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}
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/* Step size */
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float step = (chip->speed == STATE_FAST) ? 2.0f : 0.5f;
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/* Rising */
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if (chip->state == STATE_RISING) {
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chip->bpm += step;
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if (chip->bpm >= target) {
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chip->bpm = target;
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chip->state = STATE_NORMAL;
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}
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}
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/* Falling */
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if (chip->state == STATE_FALLING) {
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chip->bpm -= step;
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if (chip->bpm <= target) {
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chip->bpm = target;
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chip->state = STATE_NORMAL;
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}
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}
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update_output_voltage(chip);
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}
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/* -------------------------------------------------- */
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/* Init */
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void chip_init(void) {
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printf("Heart Rate chip init\n");
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chip_state_t *chip = calloc(1, sizeof(chip_state_t));
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/* Attribute: target BPM */
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chip->pulseValue = attr_init("pulseValue", 100);
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chip->bpm = 100.0f;
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chip->last_target = 100;
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chip->state = STATE_NORMAL;
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chip->speed = STATE_SLOW;
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chip->out_pin = pin_init("OUT", ANALOG);
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chip->btn_pin = pin_init("BTN", INPUT); // pull-down switch
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timer_config_t update_cfg = {.callback = update_cb, .user_data = chip};
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chip->update_timer = timer_init(&update_cfg);
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/* 50 ms update rate */
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timer_start(chip->update_timer, 50000, true);
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}
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