Add Logitech G27 shifter fix and SPI3 support for wheel rim buttons

## ShifterAnalog G27 Mode Fix
- Fix SPI clock configuration for 74HC165 (CLKPhase, CLKPolarity)
- Add CS polarity configuration for active-low operation
- Change to synchronous SPI read for reliable button reading
- Fix CS pin index off-by-one error in setMode() and setCSPin()
- Add startRead() method to trigger SPI before processing data

## SPI Buttons 3 (SPI3 Support)
- Add SPI_Buttons_3 class using SPI3 peripheral for separate button source
- Required because 74HC165 lacks tri-state output (cannot share MISO)
- Allows G27 shifter (SPI2) and wheel rim (SPI3) to work simultaneously
- SPI3 pins: PC10 (SCK), PC11 (MISO), PA15 (CS1)

## Hardware Configuration (F407VG)
- Reduce SPI3 baud rate for reliable 74HC165 communication
- Initialize SPI CS pins HIGH (inactive) to prevent bus contention
- Enable SPIBUTTONS3 feature flag

## Documentation
- Add complete wiring guide for all G27 components
- Add technical reports documenting bugs and solutions
- Bilingual documentation (English/Portuguese)

Tested with Logitech G27 on STM32F407VET6 board.

Made-with: Cursor

Author: Orlando Eduardo Pereira

Firmware/FFBoard/UserExtensions/Inc/SPIButtons.h

@@ -35,7 +35,7 @@ struct ButtonSourceConfig{
 class SPI_Buttons: public ButtonSource,public CommandHandler,public SPIDevice {
 
 	enum class SPIButtons_commands : uint32_t {
-		mode,btncut,btnpol,btnnum,cs,spispeed
+		mode,btncut,btnpol,btnnum,cs,spispeed,debug,syncread
 	};
 
 public:
@@ -45,13 +45,14 @@ class SPI_Buttons: public ButtonSource,public CommandHandler,public SPIDevice {
 	virtual ~SPI_Buttons();
 
 	uint8_t readButtons(uint64_t* buf);
+	uint16_t getBtnNum() override; // Override to return conf.numButtons
 
 	CommandStatus command(const ParsedCommand& cmd,std::vector<CommandReply>& replies) override;
 	void registerCommands();
 	virtual std::string getHelpstring(){return "SPI 2 Button";}
 
 	void saveFlash();
-	void restoreFlash();
+	virtual void restoreFlash();
 
 	const uint8_t maxButtons = 64;
 	std::string printModes(const std::vector<std::string>& names);
@@ -63,32 +64,29 @@ class SPI_Buttons: public ButtonSource,public CommandHandler,public SPIDevice {
 	void setSpiSpeed(uint8_t speedPreset);
 
 protected:
-	SPI_Buttons(uint16_t configuration_address, uint16_t configuration_address_2);
-
-private:
+	SPI_Buttons(uint16_t configuration_address, uint16_t configuration_address_2, SPIPort* spiPort = &external_spi, uint8_t instance = 0);
 	uint16_t configuration_address;
 	uint16_t configuration_address_2;
-	bool ready = false;
 	void setConfig(ButtonSourceConfig config);
 	virtual ButtonSourceConfig* getConfig();
-	void process(uint64_t* buf);
-	uint8_t bytes = 4;
+
+private:
+	bool ready = false;
 	uint64_t mask = 0xff;
 	uint8_t offset = 0;
 
-	ButtonSourceConfig conf;
+	static constexpr std::array<uint32_t,3> speedPresets= {SPI_BAUDRATEPRESCALER_16,SPI_BAUDRATEPRESCALER_32,SPI_BAUDRATEPRESCALER_64};
 
+protected:
+	void process(uint64_t* buf);
+	uint8_t bytes = 4;
 	uint8_t spi_buf[4] = {0};
-
-	static constexpr std::array<uint32_t,3> speedPresets= {SPI_BAUDRATEPRESCALER_16,SPI_BAUDRATEPRESCALER_32,SPI_BAUDRATEPRESCALER_64};
+	ButtonSourceConfig conf;
 };
 
 class SPI_Buttons_1 : public SPI_Buttons {
 public:
-	SPI_Buttons_1()
-		: SPI_Buttons{ADR_SPI_BTN_1_CONF, ADR_SPI_BTN_1_CONF_2} {
-			setInstance(0);
-		}
+	SPI_Buttons_1();
 
 	const ClassIdentifier getInfo() override;
 	static ClassIdentifier info;
@@ -98,14 +96,24 @@ class SPI_Buttons_1 : public SPI_Buttons {
 
 class SPI_Buttons_2 : public SPI_Buttons {
 public:
-	SPI_Buttons_2()
-		: SPI_Buttons{ADR_SPI_BTN_2_CONF, ADR_SPI_BTN_2_CONF_2} {
-			setInstance(1);
-		}
+	SPI_Buttons_2();
+
+	const ClassIdentifier getInfo() override;
+	static ClassIdentifier info;
+	static bool isCreatable();
+};
+
+class SPI_Buttons_3 : public SPI_Buttons {
+public:
+	SPI_Buttons_3();
 
 	const ClassIdentifier getInfo() override;
 	static ClassIdentifier info;
 	static bool isCreatable();
+
+	void restoreFlash() override; // Override to set default values
+	uint8_t readButtons(uint64_t* buf) override; // Override to use synchronous read for SPI3
+	std::string getHelpstring() override {return "SPI 3 Button (SPI3)";}
 };
 
 #endif /* SPIBUTTONS_H_ */

Firmware/FFBoard/UserExtensions/Inc/ShifterAnalog.h

@@ -63,11 +63,14 @@ enum class ShifterAnalog_commands : uint32_t{
 		G27ShifterButtonClient(OutputPin& csPin);
 
 		static constexpr int numUserButtons{12};
+		static constexpr int bytesToRead{2}; // 16 buttons = 2 bytes (same as SPI Buttons with 16 buttons)
 
 		uint16_t getUserButtons();
 		bool getReverseButton();
-	private:
-		uint16_t buttonStates{0};
+		void startRead(); // Start a new DMA read (like SPI_Buttons does)
+		void spiRxCompleted(SPIPort* port) override; // Called when DMA completes
+
+		uint8_t spi_buf[2]{0}; // Buffer for SPI read (2 bytes for 16 buttons) - DMA writes directly here
 
 	};
 

Firmware/FFBoard/UserExtensions/Inc/eeprom_addresses.h

@@ -1,13 +1,13 @@
-/*		
- * eeprom_addresses.h		
- *		
- *  Created on: 24.01.2020		
- *  Author: Yannick		
- *		
- *	/!\ Generated from the file memory_map.csv 
-   / ! \ DO NOT EDIT THIS DIRECTLY !!!	
- */			
-		
+/*
+ * eeprom_addresses.h
+ *
+ *  Created on: 24.01.2020
+ *  Author: Yannick
+ *
+ *	/!\ Generated from the file memory_map.csv
+   / ! \ DO NOT EDIT THIS DIRECTLY !!!
+ */
+
 #ifndef EEPROM_ADDRESSES_H_
 #define EEPROM_ADDRESSES_H_
 
@@ -21,19 +21,19 @@ extern const uint16_t VirtAddVarTab[NB_OF_VAR];
 extern const uint16_t exportableFlashAddresses[NB_EXPORTABLE_ADR];
 
 
-		
-/* Add your addresses here. 0xffff is invalid as it marks an erased field.		
-Anything below 0x00ff is reserved for system variables.		
-		
-Use ranges that are clear to distinguish between configurations. Address ranges can have gaps.		
-Label the names clearly.		
-Example: 0x0100 - 0x01ff for one class and 0x0200-0x02ff for another class would be reasonable even if they each need only 3 variables		
-		
-		
-Important: Add your variable to the VirtAddVarTab[NB_OF_VAR] array in eeprom_addresses.c!		
-		
-Tip to check if a cell is intialized:		
-uint16_t EE_ReadVariable(uint16_t VirtAddress, uint16_t* Data) will return 1 if the address is not found or 0 if it was found.		
+
+/* Add your addresses here. 0xffff is invalid as it marks an erased field.
+Anything below 0x00ff is reserved for system variables.
+
+Use ranges that are clear to distinguish between configurations. Address ranges can have gaps.
+Label the names clearly.
+Example: 0x0100 - 0x01ff for one class and 0x0200-0x02ff for another class would be reasonable even if they each need only 3 variables
+
+
+Important: Add your variable to the VirtAddVarTab[NB_OF_VAR] array in eeprom_addresses.c!
+
+Tip to check if a cell is intialized:
+uint16_t EE_ReadVariable(uint16_t VirtAddress, uint16_t* Data) will return 1 if the address is not found or 0 if it was found.
 */
 // System variables
 #define ADR_HW_VERSION 1
@@ -58,6 +58,8 @@ uint16_t EE_ReadVariable(uint16_t VirtAddress, uint16_t* Data) will return 1 if
 #define ADR_SPI_BTN_2_CONF 0x205
 #define ADR_SPI_BTN_1_CONF_2 0x206
 #define ADR_SPI_BTN_2_CONF_2 0x207
+#define ADR_SPI_BTN_3_CONF 0x209
+#define ADR_SPI_BTN_3_CONF_2 0x20A
 #define ADR_LOCAL_BTN_CONF_3 0x208 // Pulse mask
 // Local encoder
 #define ADR_ENCLOCAL_CPR 0x210

Firmware/FFBoard/UserExtensions/Src/ButtonSources.cpp

@@ -24,6 +24,9 @@ const std::vector<class_entry<ButtonSource>> ButtonSource::all_buttonsources =
 #ifdef SPIBUTTONS2
 		add_class<SPI_Buttons_2,ButtonSource>(2),
 #endif
+#ifdef SPIBUTTONS3
+		add_class<SPI_Buttons_3,ButtonSource>(6),
+#endif
 #ifdef SHIFTERBUTTONS
 		add_class<ShifterAnalog,ButtonSource>(3),
 #endif