Implement solar sensor processing

2 files changed, 70 insertions, 16 deletions

diff --git a/src/GBACart.cpp b/src/GBACart.cpp
index 75bc1dc..5b81900 100644
--- a/src/GBACart.cpp
+++ b/src/GBACart.cpp
@@ -461,15 +461,6 @@ const char SOLAR_SENSOR_GAMECODES[10][5] =
 };

 

 

-struct GPIO

-{

-    bool has_solar_sensor;

-    u16 data;

-    u16 direction;

-    u16 control;

-};

-

-

 bool CartInserted;

 u8* CartROM;

 u32 CartROMSize;

@@ -503,6 +494,7 @@ void Reset()
     CartGPIO = {};

 

     GBACart_SRAM::Reset();

+    GBACart_SolarSensor::Reset();

 }

 

 void DoSavestate(Savestate* file)

@@ -578,7 +570,7 @@ void WriteGPIO(u32 addr, u16 val)
         case 0xC4:

             CartGPIO.data &= ~CartGPIO.direction;

             CartGPIO.data |= val & CartGPIO.direction;

-            // TODO: process pins

+            if (CartGPIO.has_solar_sensor) GBACart_SolarSensor::Process(&CartGPIO);

             break;

         case 0xC6:

             CartGPIO.direction = val;

@@ -593,17 +585,60 @@ void WriteGPIO(u32 addr, u16 val)
     // write the GPIO values in the ROM (if writable)

     if (CartGPIO.control & 1)

     {

-        *(u16*)&CartROM[addr] = CartGPIO.data;

-        *(u16*)&CartROM[addr + 2] = CartGPIO.direction;

-        *(u16*)&CartROM[addr + 4] = CartGPIO.control;

+        *(u16*)&CartROM[0xC4] = CartGPIO.data;

+        *(u16*)&CartROM[0xC6] = CartGPIO.direction;

+        *(u16*)&CartROM[0xC8] = CartGPIO.control;

     }

     else

     {

         // GBATEK: "in write-only mode, reads return 00h (or [possibly] other data (...))"

         // ambiguous, but mGBA sets ROM to 00h when switching to write-only, so do the same

-        *(u16*)&CartROM[addr] = 0;

-        *(u16*)&CartROM[addr + 2] = 0;

-        *(u16*)&CartROM[addr + 4] = 0;

+        *(u16*)&CartROM[0xC4] = 0;

+        *(u16*)&CartROM[0xC6] = 0;

+        *(u16*)&CartROM[0xC8] = 0;

+    }

+}

+

+}

+

+

+namespace GBACart_SolarSensor

+{

+

+bool LightEdge;

+u8 LightCounter;

+u8 LightSample;

+u8 LightLevel; // 0-10 range

+

+// levels from mGBA

+const int GBA_LUX_LEVELS[11] = { 0, 5, 11, 18, 27, 42, 62, 84, 109, 139, 183 };

+#define LIGHT_VALUE (0xFF - (0x16 + GBA_LUX_LEVELS[LightLevel]))

+

+

+void Reset()

+{

+    LightEdge = false;

+    LightCounter = 0;

+    LightSample = 0xFF;

+    LightLevel = 0;

+}

+

+void Process(GBACart::GPIO* gpio)

+{

+    if (gpio->data & 4) return; // Boktai chip select

+    if (gpio->data & 2) // Reset

+    {

+        LightCounter = 0;

+        LightSample = LIGHT_VALUE;

+    }

+    if (gpio->data & 1 && LightEdge) LightCounter++;

+

+    LightEdge = !(gpio->data & 1);

+

+    bool sendBit = LightCounter >= LightSample;

+    if (gpio->control & 1)

+    {

+        gpio->data = (gpio->data & gpio->direction) | ((sendBit << 3) & ~gpio->direction & 0xF);

     }

 }

 

diff --git a/src/GBACart.h b/src/GBACart.h
index 22a3a60..32a2171 100644
--- a/src/GBACart.h
+++ b/src/GBACart.h
@@ -43,6 +43,14 @@ void Write32(u32 addr, u32 val);
 namespace GBACart

 {

 

+struct GPIO

+{

+    bool has_solar_sensor;

+    u16 data;

+    u16 direction;

+    u16 control;

+};

+

 extern bool CartInserted;

 extern u8* CartROM;

 extern u32 CartROMSize;

@@ -59,4 +67,15 @@ void WriteGPIO(u32 addr, u16 val);
 

 }

 

+

+namespace GBACart_SolarSensor

+{

+

+extern u8 LightLevel;

+

+void Reset();

+void Process(GBACart::GPIO* gpio);

+

+}

+

 #endif // GBACART_H