Fan fixes

hardware/firmware/box_rp2040/flash.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -euo pipefail
+
+cdir="$(dirname "$(readlink -f "${0}")")"
+
+echo "Building firmware..."
+"${cdir}"/build.sh
+
+echo "Flashing firmware..."
+"$cdir"/../tools/flash_rp2040_firmware.sh "$cdir"/build/src/box_rp2040.elf

hardware/firmware/box_rp2040/src/pwr_brd_ctl/fan_ctl.c

@@ -7,16 +7,25 @@
 #include "fan_ctl_regs.h"
 #include "pwr_brd_ctl.h"
 
-uint64_t time_next_cmd[NUMFAN];
 uint16_t desired_fan_speed[NUMFAN];
+uint16_t fan_calibrated[NUMFAN][FAN_MAX_PWM+1];
+unsigned int fan_state = 0;
+bool fan_error[NUMFAN];
 
 void fan_ctl_init() {
     uint64_t now = time_us_64();
 
     for (int i = 0; i < NUMFAN; i++) {
-        time_next_cmd[i] = now;
         desired_fan_speed[i] = DESIRED_RPM;
+	fan_error[i] = false;
+
+	for (int j = 0; j < FAN_MAX_PWM; j++) {
+            fan_calibrated[i][j] = 0;
+	}
     }
+
+    // Turn off the second fan by default, having both fans on makes it very noisy
+    desired_fan_speed[1] = 0;
 }
 
 bool fan_ctl_i2c_read(uint8_t reg_id, uint8_t* dest) {
@@ -43,7 +52,6 @@ void pwr_brd_fan_init() {
 
     fan_ctl_set_pwm_frequency(0, 0, 0, 0, 0);
     for (int i = 0; i < NUMFAN; i++) {
-        time_next_cmd[i] = now;
         desired_fan_speed[i] = DESIRED_RPM;
     }
 }
@@ -156,59 +164,104 @@ Standard fan control:
 
 */
 
-void fan_ctl_task() {
-    uint64_t now = time_us_64();
-
-    for (int i = 0; i < NUMFAN; i++) {
-        if (now < time_next_cmd[i]) {
-            continue;
-        }
+uint8_t fan_get_stall_speed(uint8_t fan_id) {
+    for (int i = FAN_MAX_PWM; i > 0; i-- ) {
+        if (fan_calibrated[fan_id][i] == 0) {
+            return i;
+	}
+    }
+}
 
-        time_next_cmd[i] = now + CMD_WAIT_TIME_US;
+void fan_ctl_task_calibrate() {
+    static uint64_t fancal_last = 0;
+    static uint8_t fancal_step = FAN_MAX_PWM;
+    uint64_t now = time_us_64();
+    if (now < (fancal_last + 2000000)) {
+	return;
+    }
 
+    io_say_f("Calibration step %d\r\n", fancal_step);
+    // First iteration doesn't store the values since the fans still
+    // have to spin up
+    if (fancal_last > 0) {
         uint16_t fanspeed;
-        fan_ctl_get_fan_speed(i, &fanspeed);
+        for(int i = 0; i < NUMFAN; i++) {
+            fan_ctl_get_fan_speed(i, &fanspeed);
+            fan_calibrated[i][fancal_step] = fanspeed;
 
-        if (desired_fan_speed[i] == 0) {
-            // fan should be off
-
-            if (fanspeed > 0) {
-                // turn off fan
-                fan_ctl_set_pwm(i, 0);
-            }
-            // otherwise, fan is off, as requested
-
-            continue;
-        }
-
-	int difference = desired_fan_speed[i] - fanspeed;
-        uint8_t pwm;
-        fan_ctl_get_pwm(i, &pwm);
-	float smooth = 0.0005f;
-	pwm += ((difference>>2) * (1.0f - exp(-smooth)));
-        fan_ctl_set_pwm(i, pwm);
-
-        if (pwm > FAN_MAX_PWM) {
-            // PWM was set by the fan controller's default power on value
-            // bring it back down to the max value
-            fan_ctl_set_pwm(i, FAN_MAX_PWM);
-            continue;
+	    if (fancal_step == FAN_MAX_PWM && fanspeed == 0) {
+                fan_error[i] = true;
+	    }
         }
+	fancal_step--;
+	if (fancal_step == 0) {
+	    // End calibration and move to the next state
+            fan_state = FAN_STATE_RUN;
+            /*
+            io_say_f("Calibration finished\r\n");
+            for (int fan =0; fan <NUMFAN;fan++){
+                io_say_f("FAN %d: ", fan);
+                if (fan_error[fan]) {
+                    io_say_f("disconnected");
+                } else {
+                    for(int step=0;step<FAN_MAX_PWM;step++){
+                        io_say_f("%d, ", fan_calibrated[fan][step]);
+                    }
+                }
+                io_say_f("\r\n");
+	    }
+            */
+	    return;
+	}
+    }
 
-        if (fanspeed == 0) {
-            // initial spin-up
-            // set to full speed
+    for (int i = 0; i < NUMFAN; i++) {
+        if(!fan_ctl_set_pwm(i, fancal_step)) {
+            // io_say_f("Failed to set PWM on fan %d\r\n", i);
+	}
+    }
+    fancal_last = time_us_64();
+}
 
-            if (pwm >= FAN_MAX_PWM) {
-                // fan is already at full speed
-                // it could be defective or disconnected
-                // nothing to do
-                continue;
-            }
+void fan_ctl_task_run() {
+    uint64_t now = time_us_64();
+    static uint64_t time_last = 0;
+    if (now < (time_last + CMD_WAIT_TIME_US)) {
+	return;
+    }
 
-            fan_ctl_set_pwm(i, FAN_MAX_PWM);
+    for (int i = 0; i < NUMFAN; i++ ) {
+	if (fan_error[i]) {
             continue;
+	}
+        uint16_t fanspeed;
+        fan_ctl_get_fan_speed(i, &fanspeed);
+
+	// Anti-stall
+	if (desired_fan_speed[i] > 0 && fanspeed == 0) {
+	    // io_say_f("Stall on fan %d\r\n", i);
+            fan_ctl_set_pwm(i, fan_get_stall_speed(i) + 2);
+	    continue;
+	}
+
+	// Apply requested fan speed relative to stall speed
+        uint8_t new_rpm = 0;
+        if (desired_fan_speed[i] > 0) {
+    	    new_rpm = fan_get_stall_speed(i) + desired_fan_speed[i];
         }
+        fan_ctl_set_pwm(i, new_rpm);
+    }
+    time_last = time_us_64();
+}
 
+void fan_ctl_task() {
+    switch (fan_state) {
+        case FAN_STATE_CALIBRATE:
+	    return fan_ctl_task_calibrate();
+	case FAN_STATE_RUN:
+	    return fan_ctl_task_run();
+	default:
+	    fan_state = FAN_STATE_CALIBRATE;
+	    break;
     }
 }

hardware/firmware/box_rp2040/src/pwr_brd_ctl/fan_ctl.h

@@ -5,13 +5,16 @@
 
 #define FAN_TACH_CONSTANT (7864320)
 #define CMD_WAIT_TIME_US (3000 * 1000)
-#define DESIRED_RPM (5000)
+#define DESIRED_RPM (1)
 #define DESIRED_RPM_THRESH_UPPER (1000)
 #define DESIRED_RPM_THRESH_LOWER (2000)
 #define FAN_MIN_HEALTHY_RPM (3000)
 #define FAN_MAX_HEALTHY_RPM (10000)
 #define NUMFAN (5)
-#define FAN_MAX_PWM (10)
+#define FAN_MAX_PWM (6)
+
+#define FAN_STATE_CALIBRATE (0)
+#define FAN_STATE_RUN (1)
 
 bool fan_ctl_get_fan_speed(uint8_t fan_id, uint16_t* dest);
 bool fan_ctl_get_fan_status(uint8_t* dest);