🐛 Fix Fast PWM on AVR (MarlinFirmware#25030)

Followup to MarlinFirmware#25005
pierre-quelin · Dec 16, 2022 · 86a10dc · 86a10dc
1 parent ecdf07f
commit 86a10dc
Showing 1 changed file with 5 additions and 5 deletions.
diff --git a/Marlin/src/HAL/AVR/fast_pwm.cpp b/Marlin/src/HAL/AVR/fast_pwm.cpp
@@ -146,11 +146,11 @@ void MarlinHAL::set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
  LIMIT(res_pc_temp, 1U, maxtop);
 
  // Calculate frequencies of test prescaler and resolution values
- const int f_diff = ABS(f - int(f_desired)),
- f_fast_temp = (F_CPU) / (p * (1 + res_fast_temp)),
-   f_fast_diff = ABS(f_fast_temp - int(f_desired)),
- f_pc_temp = (F_CPU) / (2 * p * res_pc_temp),
- f_pc_diff = ABS(f_pc_temp - int(f_desired));
+ const uint16_t f_fast_temp = (F_CPU) / (p * (1 + res_fast_temp)),
+  f_pc_temp = (F_CPU) / (2 * p * res_pc_temp);
+ const int f_diff  = _MAX(f, f_desired) - _MIN(f, f_desired),
+  f_fast_diff = _MAX(f_fast_temp, f_desired) - _MIN(f_fast_temp, f_desired),
+  f_pc_diff  = _MAX(f_pc_temp, f_desired) - _MIN(f_pc_temp, f_desired);
 
  if (f_fast_diff < f_diff && f_fast_diff <= f_pc_diff) { // FAST values are closest to desired f
  // Set the Wave Generation Mode to FAST PWM