✨ MAX31865 Bed settings (#27611)

Author: ellensp

Marlin/Configuration.h

@@ -599,6 +599,10 @@
   #define MAX31865_SENSOR_OHMS_2      100
   #define MAX31865_CALIBRATION_OHMS_2 430
 #endif
+#if TEMP_SENSOR_IS_MAX_TC(BED)
+  #define MAX31865_SENSOR_OHMS_BED      100
+  #define MAX31865_CALIBRATION_OHMS_BED 430
+#endif
 
 #if HAS_E_TEMP_SENSOR
   #define TEMP_RESIDENCY_TIME         10  // (seconds) Time to wait for hotend to "settle" in M109

Marlin/Configuration_adv.h

@@ -174,9 +174,10 @@
  * Thermocouple Options — for MAX6675 (-2), MAX31855 (-3), and MAX31865 (-5).
  */
 //#define TEMP_SENSOR_FORCE_HW_SPI                // Ignore SCK/MOSI/MISO pins; use CS and the default SPI bus.
-//#define MAX31865_SENSOR_WIRES_0 2               // (2-4) Number of wires for the probe connected to a MAX31865 board.
-//#define MAX31865_SENSOR_WIRES_1 2
-//#define MAX31865_SENSOR_WIRES_2 2
+//#define MAX31865_SENSOR_WIRES_0   2             // (2-4) Number of wires for the probe connected to a MAX31865 board.
+//#define MAX31865_SENSOR_WIRES_1   2
+//#define MAX31865_SENSOR_WIRES_2   2
+//#define MAX31865_SENSOR_WIRES_BED 2
 
 //#define MAX31865_50HZ_FILTER                    // Use a 50Hz filter instead of the default 60Hz.
 //#define MAX31865_USE_READ_ERROR_DETECTION       // Treat value spikes (20°C delta in under 1s) as read errors.
@@ -188,6 +189,7 @@
 //#define MAX31865_WIRE_OHMS_0              0.95f // For 2-wire, set the wire resistances for more accurate readings.
 //#define MAX31865_WIRE_OHMS_1              0.0f
 //#define MAX31865_WIRE_OHMS_2              0.0f
+//#define MAX31865_WIRE_OHMS_BED            0.0f
 
 /**
  * Hephestos 2 24V heated bed upgrade kit.

Marlin/src/HAL/shared/Delay.h

@@ -174,6 +174,9 @@ void calibrate_delay_loop();
 
   // Delay in microseconds
   #define DELAY_US(x) DELAY_CYCLES((x) * ((F_CPU) / 1000000UL))
+
+  #define DELAY_CYCLES_VAR DELAY_CYCLES
+
 #else
 
   #error "Unsupported MCU architecture"

Marlin/src/inc/SanityCheck.h

@@ -2121,6 +2121,13 @@ static_assert(NUM_SERVOS <= NUM_SERVO_PLUGS, "NUM_SERVOS (or some servo index) i
     #error "MAX31865_SENSOR_OHMS_2 and MAX31865_CALIBRATION_OHMS_2 must be set if TEMP_SENSOR_2/TEMP_SENSOR_REDUNDANT is MAX31865."
   #endif
 #endif
+#if TEMP_SENSOR_BED_IS_MAX31865
+  #if !defined(MAX31865_SENSOR_WIRES_BED) || !WITHIN(MAX31865_SENSOR_WIRES_BED, 2, 4)
+    #error "MAX31865_SENSOR_WIRES_BED must be defined as an integer between 2 and 4."
+  #elif !defined(MAX31865_SENSOR_OHMS_BED) || !defined(MAX31865_CALIBRATION_OHMS_BED)
+    #error "MAX31865_SENSOR_OHMS_BED and MAX31865_CALIBRATION_OHMS_BED must be set if TEMP_SENSOR_BED is MAX31865."
+  #endif
+#endif
 
 /**
  * Redundant temperature sensor config