panda/board/drivers/fan.h

96 lines
2.9 KiB
C

struct fan_state_t {
uint16_t tach_counter;
uint16_t rpm;
uint16_t target_rpm;
uint8_t power;
float error_integral;
uint8_t stall_counter;
uint8_t stall_threshold;
uint8_t total_stall_count;
uint8_t cooldown_counter;
} fan_state_t;
struct fan_state_t fan_state;
const float FAN_I = 0.001f;
const uint8_t FAN_TICK_FREQ = 8U;
const uint8_t FAN_STALL_THRESHOLD_MIN = 3U;
const uint8_t FAN_STALL_THRESHOLD_MAX = 8U;
void fan_set_power(uint8_t percentage) {
fan_state.target_rpm = ((current_board->fan_max_rpm * CLAMP(percentage, 0U, 100U)) / 100U);
}
void llfan_init(void);
void fan_init(void) {
fan_state.stall_threshold = FAN_STALL_THRESHOLD_MIN;
fan_state.cooldown_counter = current_board->fan_enable_cooldown_time * FAN_TICK_FREQ;
llfan_init();
}
// Call this at FAN_TICK_FREQ
void fan_tick(void) {
if (current_board->fan_max_rpm > 0U) {
// Measure fan RPM
uint16_t fan_rpm_fast = fan_state.tach_counter * (60U * FAN_TICK_FREQ / 4U); // 4 interrupts per rotation
fan_state.tach_counter = 0U;
fan_state.rpm = (fan_rpm_fast + (3U * fan_state.rpm)) / 4U;
// Stall detection
bool fan_stalled = false;
if (current_board->fan_stall_recovery) {
if (fan_state.target_rpm > 0U) {
if (fan_rpm_fast == 0U) {
fan_state.stall_counter = MIN(fan_state.stall_counter + 1U, 255U);
} else {
fan_state.stall_counter = 0U;
}
if (fan_state.stall_counter > (fan_state.stall_threshold*FAN_TICK_FREQ)) {
fan_stalled = true;
fan_state.stall_counter = 0U;
fan_state.stall_threshold = CLAMP(fan_state.stall_threshold + 2U, FAN_STALL_THRESHOLD_MIN, FAN_STALL_THRESHOLD_MAX);
fan_state.total_stall_count += 1U;
// datasheet gives this range as the minimum startup duty
fan_state.error_integral = CLAMP(fan_state.error_integral, 20.0f, 45.0f);
}
} else {
fan_state.stall_counter = 0U;
fan_state.stall_threshold = FAN_STALL_THRESHOLD_MIN;
}
}
#ifdef DEBUG_FAN
puth(fan_state.target_rpm);
print(" "); puth(fan_rpm_fast);
print(" "); puth(fan_state.power);
print(" "); puth(fan_state.stall_counter);
print("\n");
#endif
// Cooldown counter
if (fan_state.target_rpm > 0U) {
fan_state.cooldown_counter = current_board->fan_enable_cooldown_time * FAN_TICK_FREQ;
} else {
if (fan_state.cooldown_counter > 0U) {
fan_state.cooldown_counter--;
}
}
// Update controller
if (fan_state.target_rpm == 0U) {
fan_state.error_integral = 0.0f;
} else {
float error = fan_state.target_rpm - fan_rpm_fast;
fan_state.error_integral += FAN_I * error;
}
fan_state.power = CLAMP(fan_state.error_integral, 0U, 100U);
// Set PWM and enable line
pwm_set(TIM3, 3, fan_state.power);
current_board->set_fan_enabled(!fan_stalled && ((fan_state.target_rpm > 0U) || (fan_state.cooldown_counter > 0U)));
}
}