PWM: slightly modify PWM duty cycle calculations

main_fw/src/main.c

@@ -27,15 +27,15 @@ uint16_t frpms_lin[3];
 
 #define TOTAL_PWM_CLOCKS 255
 
-uint16_t curr_pwm_duty1000_1 __xMR = 10;
-uint16_t curr_pwm_duty1000_2 __xMR = 10;
-uint16_t curr_pwm_duty1000_3 __xMR = 10;
+int16_t curr_pwm_duty1000_1 __xMR = 10;
+int16_t curr_pwm_duty1000_2 __xMR = 10;
+int16_t curr_pwm_duty1000_3 __xMR = 10;
 
 #define FAN_RAMPUP 800
 
-uint16_t goal_pwm_duty1000_1 __xMR = FAN_RAMPUP;
-uint16_t goal_pwm_duty1000_2 __xMR = FAN_RAMPUP;
-uint16_t goal_pwm_duty1000_3 __xMR = FAN_RAMPUP;
+int16_t goal_pwm_duty1000_1 __xMR = FAN_RAMPUP;
+int16_t goal_pwm_duty1000_2 __xMR = FAN_RAMPUP;
+int16_t goal_pwm_duty1000_3 __xMR = FAN_RAMPUP;
 
 static uint16_t iter __xMR;
 static uint16_t fan_ramp_up_count __xMR = 0;
@@ -161,9 +161,13 @@ void __xMR update_pwm()
                 curr_pwm_duty1000_3 = 0;
         }
 
-	pwm_set_parameters(&PWM_0, TOTAL_PWM_CLOCKS, TOTAL_PWM_CLOCKS*(float)(curr_pwm_duty1000_1/1000.0));
-	pwm_set_parameters(&PWM_1, TOTAL_PWM_CLOCKS, TOTAL_PWM_CLOCKS*(float)(curr_pwm_duty1000_2/1000.0));
-	pwm_set_parameters(&PWM_2, TOTAL_PWM_CLOCKS, TOTAL_PWM_CLOCKS*(float)(curr_pwm_duty1000_3/1000.0));
+        uint16_t target_duty_1 = (TOTAL_PWM_CLOCKS*curr_pwm_duty1000_1)/1000;
+        uint16_t target_duty_2 = (TOTAL_PWM_CLOCKS*curr_pwm_duty1000_2)/1000;
+        uint16_t target_duty_3 = (TOTAL_PWM_CLOCKS*curr_pwm_duty1000_3)/1000;
+
+	pwm_set_parameters(&PWM_0, TOTAL_PWM_CLOCKS, (target_duty_1 < 255)?(target_duty_1):(254));
+        pwm_set_parameters(&PWM_1, TOTAL_PWM_CLOCKS, (target_duty_2 < 255)?(target_duty_2):(254));
+        pwm_set_parameters(&PWM_2, TOTAL_PWM_CLOCKS, (target_duty_3 < 255)?(target_duty_3):(254));
 }
 
 void __xMR adc_cb(const struct adc_async_descriptor *const descr, const uint8_t channel)