🩹 Fix STM32 CPU serial UUID (#26715)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/core/language.h

@@ -88,10 +88,6 @@
   #define MACHINE_NAME DEFAULT_MACHINE_NAME
 #endif
 
-#ifndef MACHINE_UUID
-  #define MACHINE_UUID DEFAULT_MACHINE_UUID
-#endif
-
 #define MARLIN_WEBSITE_URL "marlinfw.org"
 
 //#if !defined(STRING_SPLASH_LINE3) && defined(WEBSITE_URL)

Marlin/src/gcode/host/M115.cpp

@@ -32,7 +32,7 @@
   #include "../../feature/caselight.h"
 #endif
 
-#if ENABLED(HAS_STM32_UID) && !defined(MACHINE_UUID)
+#if !defined(MACHINE_UUID) && HAS_STM32_UID
   #include "../../libs/hex_print.h"
 #endif
 
@@ -69,24 +69,31 @@ void GcodeSuite::M115() {
     #if NUM_AXES != XYZ
       " AXIS_COUNT:" STRINGIFY(NUM_AXES)
     #endif
+    #if defined(MACHINE_UUID) || HAS_STM32_UID
+      " UUID:"
+    #endif
     #ifdef MACHINE_UUID
-      " UUID:" MACHINE_UUID
+      MACHINE_UUID
     #endif
   );
 
-  // STM32UID:111122223333
-  #if ENABLED(HAS_STM32_UID) && !defined(MACHINE_UUID)
-    // STM32 based devices output the CPU device serial number
-    // Used by LumenPnP / OpenPNP to keep track of unique hardware/configurations
-    // https://github.com/opulo-inc/lumenpnp
-    // Although this code should work on all STM32 based boards
-    SERIAL_ECHOPGM(" UUID:");
-    uint32_t *uid_address = (uint32_t*)UID_BASE;
-    for (uint8_t i = 0; i < 3; ++i) {
-      const uint32_t UID = uint32_t(READ_REG(*(uid_address)));
-      uid_address += 4U;
-      for (int B = 24; B >= 0; B -= 8) print_hex_byte(UID >> B);
-    }
+  #if !defined(MACHINE_UUID) && HAS_STM32_UID
+    /**
+     * STM32-based devices have a 96-bit CPU device serial number.
+     * Used by LumenPnP / OpenPNP to keep track of unique hardware/configurations.
+     * https://github.com/opulo-inc/lumenpnp
+     * This code should work on all STM32-based boards.
+     */
+    #if ENABLED(STM32_UID_SHORT_FORM)
+      uint32_t * const UID = (uint32_t*)UID_BASE;
+      SERIAL_ECHO(hex_long(UID[0]), hex_long(UID[1]), hex_long(UID[2]));
+    #else
+      uint16_t * const UID = (uint16_t*)UID_BASE;
+      SERIAL_ECHO(
+        F("CEDE2A2F-"), hex_word(UID[0]), '-', hex_word(UID[1]), '-', hex_word(UID[2]), '-',
+        hex_word(UID[3]), hex_word(UID[4]), hex_word(UID[5])
+      );
+    #endif
   #endif
 
   SERIAL_EOL();

Marlin/src/inc/Conditionals_adv.h

@@ -1216,11 +1216,6 @@
   #define NO_EEPROM_SELECTED 1
 #endif
 
-// Flag whether hex_print.cpp is used
-#if ANY(AUTO_BED_LEVELING_UBL, M100_FREE_MEMORY_WATCHER, DEBUG_GCODE_PARSER, TMC_DEBUG, MARLIN_DEV_MODE, DEBUG_CARDREADER, M20_TIMESTAMP_SUPPORT)
-  #define NEED_HEX_PRINT 1
-#endif
-
 // Flags for Case Light having a color property or a single pin
 #if ENABLED(CASE_LIGHT_ENABLE)
   #if ANY(CASE_LIGHT_USE_NEOPIXEL, CASE_LIGHT_USE_RGB_LED)

Marlin/src/inc/Conditionals_post.h

@@ -3298,3 +3298,15 @@
     FIL_RUNOUT5_PULLDOWN, FIL_RUNOUT6_PULLDOWN, FIL_RUNOUT7_PULLDOWN, FIL_RUNOUT8_PULLDOWN)
   #define USING_PULLDOWNS 1
 #endif
+
+// Machine UUID can come from STM32 CPU Serial Number
+#ifdef MACHINE_UUID
+  #undef HAS_STM32_UID
+#elif !HAS_STM32_UID && defined(DEFAULT_MACHINE_UUID)
+  #define MACHINE_UUID DEFAULT_MACHINE_UUID
+#endif
+
+// Flag whether hex_print.cpp is needed
+#if ANY(AUTO_BED_LEVELING_UBL, M100_FREE_MEMORY_WATCHER, DEBUG_GCODE_PARSER, TMC_DEBUG, MARLIN_DEV_MODE, DEBUG_CARDREADER, M20_TIMESTAMP_SUPPORT, HAS_STM32_UID)
+  #define NEED_HEX_PRINT 1
+#endif

Marlin/src/pins/stm32f4/pins_OPULO_LUMEN_REV3.h

@@ -44,8 +44,10 @@
 
 // I2C MCP3426 (16-Bit, 240SPS, dual-channel ADC)
 #define HAS_MCP3426_ADC
+
+// Opulo Lumen uses the CPU serial number
 #ifdef STM32F4
-  #define HAS_STM32_UID
+  #define HAS_STM32_UID                        1
 #endif
 
 //

Marlin/src/pins/stm32f4/pins_OPULO_LUMEN_REV4.h

@@ -45,6 +45,11 @@
 // I2C MCP3426 (16-Bit, 240SPS, dual-channel ADC)
 #define HAS_MCP3426_ADC
 
+// Opulo Lumen uses the CPU serial number
+#ifdef STM32F4
+  #define HAS_STM32_UID                        1
+#endif
+
 //
 // Servos
 //