Add ability to invert display on SSD1306

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Ability to invert the display orientation for SSD1306 (new configuration file option).
+
 ## [0.6.2] - 2020-10-18
 
 ### Fixed

include/config.def

@@ -38,6 +38,7 @@ CFG(type,					TLCDType,					m_LCDType,					TLCDType::None							)
 CFG(width,					int,						m_nLCDWidth,				20										)
 CFG(height,					int,						m_nLCDHeight,				2										)
 CFG(i2c_lcd_address,		int,						m_nLCDI2CLCDAddress,		0x3c,							true	)
+CFG(rotation,				TLCDRotation,				m_nLCDRotation,				TLCDRotation::Normal					)
 END_SECTION
 
 #undef BEGIN_SECTION

include/config.h

@@ -21,6 +21,7 @@
 #ifndef _config_h
 #define _config_h
 
+#include "lcd/ssd1306.h"
 #include "mt32synth.h"
 #include "rommanager.h"
 #include "utility.h"
@@ -40,6 +41,8 @@ public:
 	using TMT32EmuMIDIChannels     = CMT32SynthBase::TMIDIChannels;
 	using TMT32EmuROMSet           = CROMManager::TROMSet;
 
+	using TLCDRotation             = CSSD1306::TLCDRotation;
+
 	#define ENUM_LCDTYPE(ENUM)             \
 		ENUM(None, none)                   \
 		ENUM(HD44780FourBit, hd44780_4bit) \
@@ -71,6 +74,7 @@ private:
 	static bool ParseOption(const char* pString, TMT32EmuMIDIChannels* pOut);
 	static bool ParseOption(const char* pString, TMT32EmuROMSet* pOut);
 	static bool ParseOption(const char* pString, TLCDType* pOut);
+	static bool ParseOption(const char* pString, TLCDRotation* pOut);
 
 	static CConfig* s_pThis;
 };

include/lcd/ssd1306.h

@@ -26,11 +26,18 @@
 
 #include "lcd/mt32lcd.h"
 #include "mt32synth.h"
+#include "utility.h"
 
 class CSSD1306 : public CMT32LCD
 {
 public:
-	CSSD1306(CI2CMaster* pI2CMaster, u8 nAddress = 0x3c, u8 nHeight = 32);
+	#define ENUM_LCDROTATION(ENUM) \
+		ENUM(Normal, normal)       \
+		ENUM(Inverted, inverted)
+
+	CONFIG_ENUM(TLCDRotation, ENUM_LCDROTATION);
+
+	CSSD1306(CI2CMaster* pI2CMaster, u8 nAddress = 0x3c, u8 nHeight = 32, TLCDRotation Rotation = TLCDRotation::Normal);
 
 	// CCharacterLCD
 	virtual bool Initialize() override;
@@ -51,11 +58,10 @@ private:
 	CI2CMaster* m_pI2CMaster;
 	u8 m_nAddress;
 	u8 m_nHeight;
+	TLCDRotation m_Rotation;
 
 	// +1 to store the 0x40 command at the beginning
 	u8 m_Framebuffer[128 * 64 / 8 + 1];
-
-	static const u8 InitSequence[];
 };
 
 #endif

sdcard/mt32-pi.cfg

@@ -177,3 +177,14 @@ height = 32
 #
 # Values: 00-80 (3c*)
 i2c_lcd_address = 3c
+
+# Rotate the display output (graphical LCDs only).
+#
+# Some graphical displays support rotation. Use this option if you need to turn
+# the display around.
+#
+# Values: normal*, inverted
+#
+# normal:   No rotation
+# inverted: The display output is upside down
+rotation = normal

src/config.cpp

@@ -60,6 +60,7 @@ CONFIG_ENUM_STRINGS(TMT32EmuResamplerQuality, ENUM_RESAMPLERQUALITY);
 CONFIG_ENUM_STRINGS(TMT32EmuMIDIChannels, ENUM_MIDICHANNELS);
 CONFIG_ENUM_STRINGS(TMT32EmuROMSet, ENUM_ROMSET);
 CONFIG_ENUM_STRINGS(TLCDType, ENUM_LCDTYPE);
+CONFIG_ENUM_STRINGS(TLCDRotation, ENUM_LCDROTATION);
 
 CConfig* CConfig::s_pThis = nullptr;
 
@@ -141,3 +142,4 @@ CONFIG_ENUM_PARSER(TMT32EmuResamplerQuality);
 CONFIG_ENUM_PARSER(TMT32EmuMIDIChannels);
 CONFIG_ENUM_PARSER(TMT32EmuROMSet);
 CONFIG_ENUM_PARSER(TLCDType);
+CONFIG_ENUM_PARSER(TLCDRotation);

src/kernel.cpp

@@ -131,7 +131,7 @@ bool CKernel::Initialize(void)
 	else if (m_Config.m_LCDType == CConfig::TLCDType::HD44780I2C)
 		m_pLCD = new CHD44780I2C(&m_I2CMaster, m_Config.m_nLCDI2CLCDAddress, m_Config.m_nLCDWidth, m_Config.m_nLCDHeight);
 	else if (m_Config.m_LCDType == CConfig::TLCDType::SSD1306I2C)
-		m_pLCD = new CSSD1306(&m_I2CMaster, m_Config.m_nLCDI2CLCDAddress, m_Config.m_nLCDHeight);
+		m_pLCD = new CSSD1306(&m_I2CMaster, m_Config.m_nLCDI2CLCDAddress, m_Config.m_nLCDHeight, m_Config.m_nLCDRotation);
 
 	if (m_pLCD)
 	{

src/lcd/ssd1306.cpp

@@ -86,52 +86,12 @@ namespace
 constexpr auto FontSingle = Font<Utility::ArraySize(Font6x8), decltype(SingleColumn)>(Font6x8, SingleColumn);
 constexpr auto FontDouble = Font<Utility::ArraySize(Font6x8), decltype(DoubleColumn)>(Font6x8, DoubleColumn);
 
-const u8 CSSD1306::InitSequence[] =
-{
-	0xAE,		// Screen off
-	0x81,		// Set contrast
-		0x7F,	// 00-FF, default to half
-
-	0xA6,		// Normal display
-
-	0x20,		// Set memory addressing mode
-		0x0,	// 00 = horizontal
-	0x21,		// Set column start and end address
-		0x00,
-		0x7F,
-	0x22,		// Set page address range
-		0x00,
-		0x03,
-
-	0xA1,		// Set segment remap
-	0xA8,		// Set multiplex ratio
-		0x1F,	// Screen height - 1 (31)
-
-	0xC8,		// Set COM output scan direction
-	0xD3,		// Set display offset
-		0x00,	// None
-	0xDA,		// Set com pins hardware configuration
-		0x02,	// Alternate COM config and disable COM left/right
-
-	0xD5,		// Set display oscillator
-		0x80,	// Default value
-	0xD9,		// Set precharge period
-		0x22,	// Default value
-	0xDB,		// Set VCOMH deselected level
-		0x20,	// Default
-
-	0x8D,		// Set charge pump
-	0x14,		// VCC generated by internal DC/DC circuit
-
-	0xA4,		// Resume to RAM content display
-	0xAF		// Set display on
-};
-
-CSSD1306::CSSD1306(CI2CMaster *pI2CMaster, u8 nAddress, u8 nHeight)
+CSSD1306::CSSD1306(CI2CMaster *pI2CMaster, u8 nAddress, u8 nHeight, TLCDRotation Rotation)
 	: CMT32LCD(),
 	  m_pI2CMaster(pI2CMaster),
 	  m_nAddress(nAddress),
 	  m_nHeight(nHeight),
+	  m_Rotation(Rotation),
 
 	  m_Framebuffer{0x40}
 {
@@ -145,8 +105,52 @@ bool CSSD1306::Initialize()
 	if (!(m_nHeight == 32 || m_nHeight == 64))
 		return false;
 
+	const u8 segRemap = m_Rotation == TLCDRotation::Inverted ? 0xA0 : 0xA1;
+	const u8 comScanDir = m_Rotation == TLCDRotation::Inverted ? 0xC0 : 0xC8;
+
+	const u8 initSequence[] =
+	{
+		0xAE,		// Screen off
+		0x81,		// Set contrast
+			0x7F,	// 00-FF, default to half
+
+		0xA6,		// Normal display
+
+		0x20,		// Set memory addressing mode
+			0x0,	// 00 = horizontal
+		0x21,		// Set column start and end address
+			0x00,
+			0x7F,
+		0x22,		// Set page address range
+			0x00,
+			0x03,
+
+		segRemap,	// Set segment remap
+		0xA8,		// Set multiplex ratio
+			0x1F,	// Screen height - 1 (31)
+
+		comScanDir,	// Set COM output scan direction
+		0xD3,		// Set display offset
+			0x00,	// None
+		0xDA,		// Set com pins hardware configuration
+			0x02,	// Alternate COM config and disable COM left/right
+
+		0xD5,		// Set display oscillator
+			0x80,	// Default value
+		0xD9,		// Set precharge period
+			0x22,	// Default value
+		0xDB,		// Set VCOMH deselected level
+			0x20,	// Default value
+
+		0x8D,		// Set charge pump
+		0x14,		// VCC generated by internal DC/DC circuit
+
+		0xA4,		// Resume to RAM content display
+		0xAF		// Set display on
+	};
+
 	u8 buffer[] = {0x80, 0};
-	for (auto byte : InitSequence)
+	for (auto byte : initSequence)
 	{
 		buffer[1] = byte;
 		m_pI2CMaster->Write(m_nAddress, buffer, 2);
@@ -164,21 +168,21 @@ void CSSD1306::WriteFramebuffer() const
 void CSSD1306::SetPixel(u8 nX, u8 nY)
 {
 	// Ensure range is within 0-127 for x, 0-63 for y
-	nX &= 0x7f;
-	nY &= 0x3f;
+	nX &= 0x7F;
+	nY &= 0x3F;
 
 	// The framebuffer starts with the 0x40 byte so that we can write out the entire
 	// buffer to the I2C device in one shot, so offset by 1
-	m_Framebuffer[((nY & 0xf8) << 4) + nX + 1] |= 1 << (nY & 7);
+	m_Framebuffer[((nY & 0xF8) << 4) + nX + 1] |= 1 << (nY & 7);
 }
 
 void CSSD1306::ClearPixel(u8 nX, u8 nY)
 {
 	// Ensure range is within 0-127 for x, 0-63 for y
-	nX &= 0x7f;
-	nY &= 0x3f;
+	nX &= 0x7F;
+	nY &= 0x3F;
 
-	m_Framebuffer[((nY & 0xf8) << 4) + nX + 1] &= ~(1 << (nY & 7));
+	m_Framebuffer[((nY & 0xF8) << 4) + nX + 1] &= ~(1 << (nY & 7));
 }
 
 void CSSD1306::DrawChar(char chChar, u8 nCursorX, u8 nCursorY, bool bInverted, bool bDoubleWidth)