Revisiting HW vs SW SPI

MarlinFirmware · Jul 3, 2021 · 20075de · 20075de
1 parent 956c891
commit 20075de
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diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
@@ -401,13 +401,18 @@
  *
  * Temperature sensors available:
  *
- *  SPI RTD/Thermocouple Boards - NOTE: Ensure TEMP_n_CS_PIN is set in your pins file for each TEMP_SENSOR_n, as well as the
- *  -------                       following for Software SPI: TEMP_n_MOSI_PIN (MAX31865 only), TEMP_n_MISO_PIN, TEMP_n_SCK_PIN.
+ *  SPI RTD/Thermocouple Boards - IMPORTANT: Read the NOTE below!
+ *  -------
  *    -5 : MAX31865 with Pt100/Pt1000, 2, 3, or 4-wire  (only for sensors 0-1)
  *                  NOTE: You must uncomment/set the MAX31865_*_OHMS_n defines below.
  *    -3 : MAX31855 with Thermocouple, -200°C to +700°C (only for sensors 0-1)
  *    -2 : MAX6675  with Thermocouple, 0°C to +700°C    (only for sensors 0-1)
  *
+ *  NOTE: Ensure TEMP_n_CS_PIN is set in your pins file for each TEMP_SENSOR_n using an SPI Thermocouple. By default,
+ *        Hardware SPI on the default serial bus is used. If you have also set TEMP_n_SCK_PIN and TEMP_n_MISO_PIN,
+ *        Software SPI will be used on those ports instead. You can force Hardware SPI on the default bus in the
+ *        Configuration_adv.h file. At this time, separate Hardware SPI buses for sensors are not supported.
+ *
  *  Analog Themocouple Boards
  *  -------
  *    -4 : AD8495 with Thermocouple

diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
@@ -131,6 +131,16 @@
   #define REDUNDANT_BETA                   3950    // Beta value
 #endif
 
+/**
+ * Configuration options for MAX Thermocouples (-2, -3, -5).
+ *   FORCE_HW_SPI:   Ignore SCK/MOSI/MISO pins and just use the CS pin & default SPI bus.
+ *   MAX31865_WIRES: Set the number of wires for the probe connected to a MAX31865 board, 2-4. Default: 2
+ */
+//#define TEMP_SENSOR_FORCE_HW_SPI
+//#define MAX31865_SENSOR_WIRES_0 2
+//#define MAX31865_SENSOR_WIRES_1 2
+
+
 //
 // Hephestos 2 24V heated bed upgrade kit.
 // https://store.bq.com/en/heated-bed-kit-hephestos2

diff --git a/Marlin/src/inc/Conditionals_post.h b/Marlin/src/inc/Conditionals_post.h
@@ -827,11 +827,11 @@
     #endif
 
     // Software SPI - enable if MISO/SCK are defined.
-    #if PIN_EXISTS(TEMP_0_MISO) && PIN_EXISTS(TEMP_0_SCK)
+    #if PIN_EXISTS(TEMP_0_MISO) && PIN_EXISTS(TEMP_0_SCK) && DISABLED(TEMP_SENSOR_0_FORCE_HW_SPI)
       #if TEMP_SENSOR_0_IS_MAX31865 && !PIN_EXISTS(TEMP_0_MOSI)
-        #warning "TEMP_SENSOR_0 MAX31865 also needs TEMP_0_MOSI_PIN defined for Software SPI; defaulting to Hardware SPI."
+        #error "TEMP_SENSOR_0 MAX31865 requires TEMP_0_MOSI_PIN defined for Software SPI. To use Hardware SPI instead, undefine MISO/SCK or enable TEMP_SENSOR_0_FORCE_HW_SPI."
       #else
-        #define TEMP_SENSOR_0_USES_SW_SPI 1
+        #define TEMP_SENSOR_0_HAS_SPI_PINS 1
       #endif
     #endif
 
@@ -896,11 +896,11 @@
     #endif
 
     // Software SPI - enable if MISO/SCK are defined.
-    #if PIN_EXISTS(TEMP_1_MISO) && PIN_EXISTS(TEMP_1_SCK)
+    #if PIN_EXISTS(TEMP_1_MISO) && PIN_EXISTS(TEMP_1_SCK) && DISABLED(TEMP_SENSOR_1_FORCE_HW_SPI)
       #if TEMP_SENSOR_1_IS_MAX31865 && !PIN_EXISTS(TEMP_1_MOSI)
-        #warning "TEMP_SENSOR_1 MAX31865 also needs TEMP_1_MOSI_PIN defined for Software SPI; defaulting to Hardware SPI."
+        #error "TEMP_SENSOR_1 MAX31865 requires TEMP_1_MOSI_PIN defined for Software SPI. To use Hardware SPI instead, undefine MISO/SCK or enable TEMP_SENSOR_1_FORCE_HW_SPI."
       #else
-        #define TEMP_SENSOR_1_USES_SW_SPI 1
+        #define TEMP_SENSOR_1_HAS_SPI_PINS 1
       #endif
     #endif
 

diff --git a/Marlin/src/module/temperature.cpp b/Marlin/src/module/temperature.cpp
@@ -161,18 +161,24 @@
   #define NO_MAXTC_LIBRARIES 1
 #endif
 
-// If we have a MAX TC with SCK and MISO pins defined, and we're not using an external library,
-// the MAX TC will be read via Hardware SPI on a different pin.
-#if (TEMP_SENSOR_IS_ANY_MAX_TC(0) && PINS_EXIST(TEMP_0_SCK, TEMP_0_MOSI)) && NO_MAXTC_LIBRARIES
-  #define TEMP_SENSOR_0_USES_SEPARATE_SPI 1
+// If we have a MAX TC with SCK and MISO pins defined, it's either on a separate/dedicated Hardware
+// SPI bus, or some pins for Software SPI. Alternate Hardware SPI buses are not supported yet, so
+// your SPI options are:
+//
+//  1. Only CS pin(s) defined:                  Hardware SPI on the default bus (usually the SD card SPI).
+//  2. CS, MISO, and SCK pins defined:          Software SPI on a separate bus, as defined by MISO, SCK.
+//  3. CS, MISO, and SCK pins w/ FORCE_HW_SPI:  Hardware SPI on the default bus, ignoring MISO, SCK.
+//
+#if TEMP_SENSOR_IS_ANY_MAX_TC(0) && TEMP_SENSOR_0_HAS_SPI_PINS && DISABLED(TEMP_SENSOR_FORCE_HW_SPI)
+    #define TEMP_SENSOR_0_USES_SW_SPI 1
 #endif
-#if (TEMP_SENSOR_IS_ANY_MAX_TC(1) && PINS_EXIST(TEMP_1_SCK, TEMP_1_MOSI)) && NO_MAXTC_LIBRARIES
-  #define TEMP_SENSOR_1_USES_SEPARATE_SPI 1
+#if TEMP_SENSOR_IS_ANY_MAX_TC(1) && TEMP_SENSOR_1_HAS_SPI_PINS && DISABLED(TEMP_SENSOR_FORCE_HW_SPI)
+    #define TEMP_SENSOR_1_USES_SW_SPI 1
 #endif
 
-#if TEMP_SENSOR_0_USES_SEPARATE_SPI || TEMP_SENSOR_1_USES_SEPARATE_SPI
+#if TEMP_SENSOR_0_USES_SW_SPI || TEMP_SENSOR_1_USES_SW_SPI
   #include "../libs/private_spi.h"
-  #define MAXTC_SEPARATE_SPI 1
+  #define HAS_MAXTC_SW_SPI 1
 #endif
 
 #if ENABLED(PID_EXTRUSION_SCALING)
@@ -2022,12 +2028,6 @@ void Temperature::updateTemperaturesFromRawValues() {
   #endif
 } // Temperature::updateTemperaturesFromRawValues
 
-#if MAXTC_SEPARATE_SPI
-  //TODO: what about '55, '65?
-  template<uint8_t MisoPin, uint8_t MosiPin, uint8_t SckPin> SoftSPI<MisoPin, MosiPin, SckPin> SPIclass<MisoPin, MosiPin, SckPin>::softSPI;
-  SPIclass<TEMP_0_MISO_PIN, SD_MOSI_PIN, TEMP_0_SCK_PIN> max_tc_spi;
-#endif
-
 // Init fans according to whether they're native PWM or Software PWM
 #ifdef BOARD_OPENDRAIN_MOSFETS
   #define _INIT_SOFT_FAN(P) OUT_WRITE_OD(P, FAN_INVERTING ? LOW : HIGH)
@@ -2212,8 +2212,8 @@ void Temperature::init() {
     INIT_FAN_PIN(CONTROLLER_FAN_PIN);
   #endif
 
-  #if MAXTC_SEPARATE_SPI
-     max_tc_spi.init();
+  #if !HAS_MAXTC_LIBRARIES && HAS_MAXTC_SW_SPI
+    max_tc_spi.init();
   #endif
 
   HAL_adc_init();
@@ -2619,6 +2619,14 @@ void Temperature::disable_all_heaters() {
     #define THERMOCOUPLE_MAX_ERRORS 15
   #endif
 
+  #if !HAS_MAXTC_LIBRARIES && HAS_MAXTC_SW_SPI
+    // Initialize SoftSPI for non-lib Software SPI; Libraries take care of it themselves.
+    template<uint8_t MisoPin, uint8_t MosiPin, uint8_t SckPin>
+      SoftSPI<MisoPin, MosiPin, SckPin> SPIclass<MisoPin, MosiPin, SckPin>::softSPI;
+
+    SPIclass<TEMP_0_MISO_PIN, SD_MOSI_PIN, TEMP_0_SCK_PIN> max_tc_spi;
+  #endif
+
   /**
    * Read MAX Thermocouple temperature.
    *
@@ -2627,20 +2635,17 @@ void Temperature::disable_all_heaters() {
   int Temperature::read_max_tc(TERN_(HAS_MULTI_MAX_TC, const uint8_t hindex/*=0*/)) {
     #define MAXTC_HEAT_INTERVAL 250UL
 
-    #if HAS_MAX31855_LIBRARY
-      static uint32_t max_tc_temp = 2000;
-      #define MAX_TC_ERROR_MASK    7
-      #define MAX_TC_DISCARD_BITS 18
+    #if HAS_MAX31855
+      #define MAX_TC_ERROR_MASK    7        // D2-0: SCV, SCG, OC
+      #define MAX_TC_DISCARD_BITS 18        // Data D31-18; sign bit D31
       #define MAX_TC_SPEED_BITS    3        // (_BV(SPR1)) // clock ÷ 64
-    #elif HAS_MAX31865_LIBRARY
-      static uint16_t max_tc_temp = 2000;   // From datasheet 16 bits D15-D0
-      #define MAX_TC_ERROR_MASK    1        // D0 Bit not used
+    #elif HAS_MAX31865
+      #define MAX_TC_ERROR_MASK    1        // D0 Bit on fault only
       #define MAX_TC_DISCARD_BITS  1        // Data is in D15-D1
       #define MAX_TC_SPEED_BITS    3        // (_BV(SPR1)) // clock ÷ 64
-    #else // MAX6675 or manual SPI reading
-      static uint16_t max_tc_temp = 2000;
-      #define MAX_TC_ERROR_MASK    4
-      #define MAX_TC_DISCARD_BITS  3
+    #else // MAX6675
+      #define MAX_TC_ERROR_MASK    3        // D2 only; 1 = open circuit
+      #define MAX_TC_DISCARD_BITS  3        // Data D15-D1
       #define MAX_TC_SPEED_BITS    2        // (_BV(SPR0)) // clock ÷ 16
     #endif
 
@@ -2649,21 +2654,26 @@ void Temperature::disable_all_heaters() {
       static celsius_t max_tc_temp_previous[MAX_TC_COUNT] = { 0 };
       #define THERMO_TEMP(I) max_tc_temp_previous[I]
       #define THERMO_SEL(A,B) (hindex ? (B) : (A))
-      #define MAXTC_WRITE(V) do{ switch (hindex) { case 1: WRITE(TEMP_1_CS_PIN, V); break; default: WRITE(TEMP_0_CS_PIN, V); } }while(0)
+      #define MAXTC_CS_WRITE(V) do{ switch (hindex) { case 1: WRITE(TEMP_1_CS_PIN, V); break; default: WRITE(TEMP_0_CS_PIN, V); } }while(0)
     #else
       // When we have only 1 max tc, THERMO_SEL will pick the appropriate sensor
       // variable, and MAXTC_*() macros will be hardcoded to the correct CS pin.
       constexpr uint8_t hindex = 0;
       #define THERMO_TEMP(I) max_tc_temp
       #if TEMP_SENSOR_IS_ANY_MAX_TC(0)
         #define THERMO_SEL(A,B) A
-        #define MAXTC_WRITE(V)  WRITE(TEMP_0_CS_PIN, V)
+        #define MAXTC_CS_WRITE(V)  WRITE(TEMP_0_CS_PIN, V)
       #else
         #define THERMO_SEL(A,B) B
-        #define MAXTC_WRITE(V)  WRITE(TEMP_1_CS_PIN, V)
+        #define MAXTC_CS_WRITE(V)  WRITE(TEMP_1_CS_PIN, V)
       #endif
     #endif
 
+    static TERN(HAS_MAX31855, uint32_t, uint16_t) max_tc_temp = THERMO_SEL(
+      TEMP_SENSOR_0_MAX_TC_TMAX,
+      TEMP_SENSOR_1_MAX_TC_TMAX
+    );
+
     static uint8_t max_tc_errors[MAX_TC_COUNT] = { 0 };
 
     // Return last-read value between readings
@@ -2672,28 +2682,27 @@ void Temperature::disable_all_heaters() {
     if (PENDING(ms, next_max_tc_ms[hindex])) return int(THERMO_TEMP(hindex));
     next_max_tc_ms[hindex] = ms + MAXTC_HEAT_INTERVAL;
 
-    #if !MAXTC_SEPARATE_SPI && NO_MAXTC_LIBRARIES
-      // Initialize SPI using the default SPI bus.
-      // FIXME: spiBegin, spiRec and spiInit doesn't work when soft spi is used.
-      spiBegin();
-      spiInit(MAX_TC_SPEED_BITS);
-    #endif
+    #if NO_MAXTC_LIBRARIES
+      max_tc_temp = 0;
 
-    max_tc_temp = 0;
+      #if !MAXTC_SEPARATE_SPI && NO_MAXTC_LIBRARIES
+        // Initialize SPI using the default SPI bus.
+        // FIXME: spiBegin, spiRec and spiInit doesn't work when soft spi is used.
+        spiBegin();
+        spiInit(MAX_TC_SPEED_BITS);
+      #endif
 
-    #if NO_MAXTC_LIBRARIES
-      // Read a big-endian temperature value without using a library
-      MAXTC_WRITE(LOW);  // enable MAXTC
-      DELAY_NS(100);     // Ensure 100ns delay
+      MAXTC_CS_WRITE(LOW);  // enable MAXTC
+      DELAY_NS(100);       // Ensure 100ns delay
 
+      // Read a big-endian temperature value without using a library
       for (uint8_t i = sizeof(max_tc_temp); i--;) {
-        max_tc_temp |= TERN(MAXTC_SEPARATE_SPI, max_tc_spi.receive(), spiRec());
+        max_tc_temp |= TERN(HAS_MAXTC_SW_SPI, max_tc_spi.receive(), spiRec());
         if (i > 0) max_tc_temp <<= 8; // shift left if not the last byte
       }
 
-      MAXTC_WRITE(HIGH);  // disable MAXTC
+      MAXTC_CS_WRITE(HIGH);  // disable MAXTC
     #else
-      // TODO: a lot of this is references to the GadgetAngel ModM versions...
       #if HAS_MAX6675_LIBRARY
         MAX6675 &max6675ref = THERMO_SEL(max6675_0, max6675_1);
         max_tc_temp = max6675ref.readRaw16();
@@ -2726,7 +2735,7 @@ void Temperature::disable_all_heaters() {
         SERIAL_ERROR_START();
         SERIAL_ECHOPGM("Temp measurement error! ");
         #if HAS_MAX31855
-          SERIAL_ECHOPAIR("MAX31855 Fault : (", max_tc_temp & 0x7, ") >> ");
+          SERIAL_ECHOPAIR("MAX31855 Fault: (", max_tc_temp & 0x7, ") >> ");
           if (max_tc_temp & 0x1)
             SERIAL_ECHOLNPGM("Open Circuit");
           else if (max_tc_temp & 0x2)