diff --git a/build/libraries/snd/ARM7/snd_global.c b/build/libraries/snd/ARM7/snd_global.c
index a81dba9..6c5f74f 100644
--- a/build/libraries/snd/ARM7/snd_global.c
+++ b/build/libraries/snd/ARM7/snd_global.c
@@ -54,7 +54,7 @@ extern void PMi_ResetControl(u8 sw);
 void SND_Enable(void)
 {
     OSIntrMode enabled = OS_DisableInterrupts();
-    SND_I2SEnable();
+    I2S_Enable();
     reg_SND_SOUNDCNT_8 |= REG_SND_SOUNDCNT_8_E_MASK;
     (void)OS_RestoreInterrupts(enabled);
 }
@@ -71,7 +71,7 @@ void SND_Enable(void)
 void SND_Disable(void)
 {
     OSIntrMode enabled = OS_DisableInterrupts();
-    SND_I2SDisable();
+    I2S_Disable();
     reg_SND_SOUNDCNT_8 &= ~REG_SND_SOUNDCNT_8_E_MASK;
     (void)OS_RestoreInterrupts(enabled);
 }
@@ -111,7 +111,7 @@ void SND_Shutdown(void)
 void SND_BeginSleep(void)
 {
     // adding process for TWL
-    SND_I2SBeginSleep();
+    I2S_BeginSleep();
 
     // stop all sound
     SND_Disable();
@@ -154,7 +154,7 @@ void SND_EndSleep(void)
     SND_Enable();
 
     // adding process for TWL
-    SND_I2SEndSleep();
+    I2S_EndSleep();
 }
 
 /*---------------------------------------------------------------------------*
diff --git a/build/libraries/snd/ARM7/snd_i2s.c b/build/libraries/snd/ARM7/snd_i2s.c
index 00af7c5..ae712a8 100644
--- a/build/libraries/snd/ARM7/snd_i2s.c
+++ b/build/libraries/snd/ARM7/snd_i2s.c
@@ -35,7 +35,7 @@ static BOOL isTwl = FALSE;
     static functions
  ******************************************************************************/
 
-static void SNDi_I2SInit(void)
+static void I2Si_Init(void)
 {
     static BOOL isInitialized = FALSE;
     if (isInitialized == FALSE)
@@ -55,9 +55,9 @@ static void SNDi_I2SInit(void)
         {
             isTwl = TRUE;
             // Set default values
-            SND_I2SSetSamplingRatio(TRUE);
-            SND_I2SSetMixingRatio(8);
-            SND_I2SMute(FALSE);
+            I2S_SetSamplingRatio(TRUE);
+            I2S_SetMixingRatio(8);
+            I2S_Mute(FALSE);
         }
     }
 }
@@ -67,7 +67,7 @@ static void SNDi_I2SInit(void)
  ******************************************************************************/
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SEnable
+  Name:         I2S_Enable
 
   Description:  Enable sound master control
 
@@ -75,9 +75,9 @@ static void SNDi_I2SInit(void)
 
   Returns:      None
  *---------------------------------------------------------------------------*/
-void SND_I2SEnable(void)
+void I2S_Enable(void)
 {
-    SNDi_I2SInit();
+    I2Si_Init();
 
     if (isTwl)
     {
@@ -86,7 +86,7 @@ void SND_I2SEnable(void)
 }
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SDisable
+  Name:         I2S_Disable
 
   Description:  Disable sound master control
 
@@ -94,7 +94,7 @@ void SND_I2SEnable(void)
 
   Returns:      None
  *---------------------------------------------------------------------------*/
-void SND_I2SDisable(void)
+void I2S_Disable(void)
 {
     if (isTwl)
     {
@@ -103,7 +103,7 @@ void SND_I2SDisable(void)
 }
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SShutdown
+  Name:         I2S_Shutdown
 
   Description:  shutdown sound system
 
@@ -111,7 +111,7 @@ void SND_I2SDisable(void)
 
   Returns:      None.
  *---------------------------------------------------------------------------*/
-void SND_I2SShutdown(void)
+void I2S_Shutdown(void)
 {
 }
 
@@ -124,7 +124,7 @@ void SND_I2SShutdown(void)
 
   Returns:      None.
  *---------------------------------------------------------------------------*/
-void SND_I2SBeginSleep(void)
+void I2S_BeginSleep(void)
 {
     if (isTwl)
     {
@@ -141,7 +141,7 @@ void SND_I2SBeginSleep(void)
 
   Returns:      None.
  *---------------------------------------------------------------------------*/
-void SND_I2SEndSleep(void)
+void I2S_EndSleep(void)
 {
     if (isTwl)
     {
@@ -150,7 +150,7 @@ void SND_I2SEndSleep(void)
 }
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SMute
+  Name:         I2S_Mute
 
   Description:  Set mute status
 
@@ -158,7 +158,7 @@ void SND_I2SEndSleep(void)
 
   Returns:      None
  *---------------------------------------------------------------------------*/
-void SND_I2SMute(BOOL isMute)
+void I2S_Mute(BOOL isMute)
 {
     if (isTwl)
     {
@@ -174,7 +174,7 @@ void SND_I2SMute(BOOL isMute)
 }
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SIsMute
+  Name:         I2S_IsMute
 
   Description:  Get mute status
 
@@ -182,13 +182,13 @@ void SND_I2SMute(BOOL isMute)
 
   Returns:      TRUE if mute
  *---------------------------------------------------------------------------*/
-BOOL SND_I2SIsMute(void)
+BOOL I2S_IsMute(void)
 {
     return (BOOL)((reg_SND_I2SCNT & REG_SND_I2SCNT_MUTE_MASK) >> REG_SND_I2SCNT_MUTE_SHIFT);
 }
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SSetMixingRatio
+  Name:         I2S_SetMixingRatio
 
   Description:  Set mixing ratio
 
@@ -198,7 +198,7 @@ BOOL SND_I2SIsMute(void)
 
   Returns:      None
  *---------------------------------------------------------------------------*/
-void SND_I2SSetMixingRatio(int nitroRatio)
+void I2S_SetMixingRatio(int nitroRatio)
 {
     if (isTwl)
     {
@@ -211,7 +211,7 @@ void SND_I2SSetMixingRatio(int nitroRatio)
 }
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SGetMixingRatio
+  Name:         I2S_GetMixingRatio
 
   Description:  Set mixing ratio
 
@@ -221,13 +221,13 @@ void SND_I2SSetMixingRatio(int nitroRatio)
                               if 8, nitro sound is all.
                               if 0, DSP sound is all.
  *---------------------------------------------------------------------------*/
-int SND_I2SGetMixingRatio(void)
+int I2S_GetMixingRatio(void)
 {
     return (reg_SND_I2SCNT & REG_SND_I2SCNT_MIX_RATIO_MASK) >> REG_SND_I2SCNT_MIX_RATIO_SHIFT;
 }
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SSetSamplingRatio
+  Name:         I2S_SetSamplingRatio
 
   Description:  Set I2S sampling ratio.
                 It can be called while I2S is disabled.
@@ -236,7 +236,7 @@ int SND_I2SGetMixingRatio(void)
 
   Returns:      None
  *---------------------------------------------------------------------------*/
-void SND_I2SSetSamplingRatio(BOOL is48kHz)
+void I2S_SetSamplingRatio(BOOL is48kHz)
 {
     if (isTwl)
     {
@@ -253,7 +253,7 @@ void SND_I2SSetSamplingRatio(BOOL is48kHz)
 }
 
 /*---------------------------------------------------------------------------*
-  Name:         SND_I2SIsSamplingRatio48kHz
+  Name:         I2S_IsSamplingRatio48kHz
 
   Description:  Get I2S sampling ratio.
 
@@ -261,7 +261,7 @@ void SND_I2SSetSamplingRatio(BOOL is48kHz)
 
   Returns:      TRUE if 48 kHz. otherwise FALSE
  *---------------------------------------------------------------------------*/
-BOOL SND_I2SIsSamplingRatio48kHz(void)
+BOOL I2S_IsSamplingRatio48kHz(void)
 {
     return (BOOL)((reg_SND_I2SCNT & REG_SND_I2SCNT_CODEC_SMP_MASK) >> REG_SND_I2SCNT_CODEC_SMP_SHIFT);
 }
diff --git a/build/tests/dsp/dsp-jtag/ARM7/src/main.c b/build/tests/dsp/dsp-jtag/ARM7/src/main.c
index 5b979ea..0c08c5e 100644
--- a/build/tests/dsp/dsp-jtag/ARM7/src/main.c
+++ b/build/tests/dsp/dsp-jtag/ARM7/src/main.c
@@ -64,8 +64,8 @@ void TwlSpMain(void)
     (void)OS_EnableInterrupts();
 
     // サウンド初期化
-    SND_I2SEnable();
-    SND_I2SSetMixingRatio(0);   // dsp only
+    I2S_Enable();
+    I2S_SetMixingRatio(0);   // dsp only
     MICi_Init();
 
     // SPI初期化
diff --git a/include/twl/snd/ARM7/i2s.h b/include/twl/snd/ARM7/i2s.h
index 25c4269..6807312 100644
--- a/include/twl/snd/ARM7/i2s.h
+++ b/include/twl/snd/ARM7/i2s.h
@@ -25,10 +25,10 @@ extern "C" {
 /******************************************************************************
     public macro variables
  ******************************************************************************/
-#define SND_I2S_MIXING_NITRO_MAX    8
-#define SND_I2S_MIXING_NITRO_MIN    0
-#define SND_I2S_MIXING_DSP_MAX      0
-#define SND_I2S_MIXING_DSP_MIN      8
+#define I2S_MIXING_NITRO_MAX    8
+#define I2S_MIXING_NITRO_MIN    0
+#define I2S_MIXING_DSP_MAX      0
+#define I2S_MIXING_DSP_MIN      8
 
 /******************************************************************************
     public function declaration
@@ -36,22 +36,22 @@ extern "C" {
 
 #ifdef SDK_ARM7
 
-void    SND_I2SEnable(void);
-void    SND_I2SDisable(void);
+void    I2S_Enable(void);
+void    I2S_Disable(void);
 
-void    SND_I2SShutdown(void);
+void    I2S_Shutdown(void);
 
-void    SND_I2SBeginSleep(void);
-void    SND_I2SEndSleep(void);
+void    I2S_BeginSleep(void);
+void    I2S_EndSleep(void);
 
-void    SND_I2SMute(BOOL isMute);
-BOOL    SND_I2SIsMute(void);
+void    I2S_Mute(BOOL isMute);
+BOOL    I2S_IsMute(void);
 
-void    SND_I2SSetMixingRatio(int nitroRatio);
-int     SND_I2SGetMixingRatio(void);
+void    I2S_SetMixingRatio(int nitroRatio);
+int     I2S_GetMixingRatio(void);
 
-void    SND_I2SSetSamplingRatio(BOOL is48kHz);
-BOOL    SND_I2SIsSamplingRatio48kHz( void );
+void    I2S_SetSamplingRatio(BOOL is48kHz);
+BOOL    I2S_IsSamplingRatio48kHz( void );
 
 #endif /* SDK_ARM7 */