diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7ab29b5..a76c362 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -100,7 +100,9 @@ add_executable(unit_tests
         tests/CPU/Math/testCMP.cpp
         sources/PPU/Background.cpp
         sources/PPU/Background.hpp
-        sources/PPU/PPUUtils.cpp)
+        sources/PPU/PPUUtils.cpp
+        tests/PPU/testBackground.cpp
+        )
 
 # include criterion & coverage
 target_link_libraries(unit_tests criterion -lgcov)
@@ -217,7 +219,8 @@ add_executable(ComSquare
         sources/Models/Vector2.hpp
         sources/PPU/Background.cpp
         sources/PPU/Background.hpp
-        sources/PPU/PPUUtils.cpp)
+        sources/PPU/PPUUtils.cpp
+        )
 
 target_compile_definitions(ComSquare PUBLIC DEBUGGER_ENABLED)
 
diff --git a/sources/PPU/Background.cpp b/sources/PPU/Background.cpp
index e7a8344..c304b0d 100644
--- a/sources/PPU/Background.cpp
+++ b/sources/PPU/Background.cpp
@@ -100,13 +100,15 @@ namespace ComSquare::PPU
 		return palette;
 	}
 
-	uint8_t Background::getTilePixelReference(uint16_t addr, int nb)
+	uint8_t Background::getTilePixelReference(uint16_t addr, int index)
 	{
+		//line by line for each pixel of the line
 		uint8_t highByte = this->_vram->read_internal(addr % VRAMSIZE);
 		uint8_t lowByte = this->_vram->read_internal((addr + 1) % VRAMSIZE);
 		uint8_t secondHightByte;
 		uint8_t secondLowByte;
 		uint8_t result = 0;
+		uint8_t shift = (TILE_PIXEL_WIDTH - 1 - index);
 		// C000
 
 		switch (this->_bpp) {
@@ -115,9 +117,9 @@ namespace ComSquare::PPU
 		case 4:
 			secondHightByte =  this->_vram->read_internal((addr + 32) % VRAMSIZE);
 			secondLowByte = this->_vram->read_internal((addr + 33) % VRAMSIZE);
-			result = ((secondHightByte & (1U << (7U - nb))) | ((secondLowByte & (1U << (7U - nb))) << 1U)) >> (7U - nb - 2);
+			result = ((secondHightByte & (1U << (7U - index))) | ((secondLowByte & (1U << (7U - index))) << 1U)) >> (7U - index - 2);
 		case 2:
-			result += ((highByte & (1U << (7U - nb))) | ((lowByte & (1U << (7U - nb))) << 1U)) >> (7U - nb);
+			result += ((highByte & (1U << (7U - index))) | ((lowByte & (1U << (7U - index))) << 1U)) >> (7U - index);
 		default:
 			break;
 		}
diff --git a/sources/PPU/Background.hpp b/sources/PPU/Background.hpp
index 994d744..bca10cc 100644
--- a/sources/PPU/Background.hpp
+++ b/sources/PPU/Background.hpp
@@ -21,6 +21,8 @@ namespace ComSquare::PPU
 	class Background {
 	#define NB_CHARACTER_WIDTH 32
 	#define NB_CHARACTER_HEIGHT 32
+	#define TILE_PIXEL_WIDTH 8
+	#define TILE_PIXEL_HEIGHT 8
 	private:
 		Vector2<int> _tileMaps;
 		Vector2<int> _characterSize;
@@ -36,8 +38,10 @@ namespace ComSquare::PPU
 		void drawBgTile(uint16_t data, Vector2<int> pos);
 		//! @brief Get a palette from the number of the palette (0 - 7)
 		std::vector<uint16_t> getPalette(int nbPalette);
-		//! @brief Get the color reference of a nb pixel tile
-		uint8_t getTilePixelReference(uint16_t addr, int nb);
+		//! @brief Get the color reference of a index pixel tile
+		//! @param addr The address of the line of pixel
+		//TODO support addr as the address of the start of the tile and index goes from 0 to 63 regardless of the bpp
+		uint8_t getTilePixelReference(uint16_t addr, int index);
 		//! @brief draw a tilemap 32x32 starting at baseAddress
 		void drawBasicTileMap(uint16_t baseAddress, Vector2<int> offset);
 	public:
diff --git a/sources/PPU/PPU.cpp b/sources/PPU/PPU.cpp
index c19c735..bb1b14d 100644
--- a/sources/PPU/PPU.cpp
+++ b/sources/PPU/PPU.cpp
@@ -129,7 +129,7 @@ namespace ComSquare::PPU
 
 	uint8_t PPU::read(uint24_t addr)
 	{
-		return 0;
+	//	return 0;
 		switch (addr) {
 		case ppuRegisters::mpyl:
 			return  this->_registers._mpy.mpyl;
@@ -158,7 +158,7 @@ namespace ComSquare::PPU
 
 	void PPU::write(uint24_t addr, uint8_t data)
 	{
-		return;
+		//return;
 		switch (addr) {
 		case ppuRegisters::inidisp:
 			this->_registers._inidisp.raw = data;
diff --git a/tests/PPU/testBackground.cpp b/tests/PPU/testBackground.cpp
new file mode 100644
index 0000000..1d5de58
--- /dev/null
+++ b/tests/PPU/testBackground.cpp
@@ -0,0 +1,21 @@
+//
+// Created by cbihan on 9/29/20.
+//
+
+#include <criterion/criterion.h>
+#include <iostream>
+#include <bitset>
+#include "../tests.hpp"
+#include "../../sources/SNES.hpp"
+#include "../../sources/Memory/MemoryBus.hpp"
+#include "../../sources/PPU/PPU.hpp"
+
+using namespace ComSquare;
+
+Test(backgroundGetTilePixelReference, basicTest)
+{
+	Init()
+	snes._bus->write(0x2100, 0b11111111);
+	cr_assert_eq(snes.ppu->_registers._inidisp.fblank, true);
+	cr_assert_eq(snes.ppu->_registers._inidisp.brightness, 0xF);
+}
\ No newline at end of file