diff --git a/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_M480/m480_netif.c b/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_M480/m480_netif.c
index 2de04dc..29adfbd 100644
--- a/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_M480/m480_netif.c
+++ b/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_M480/m480_netif.c
@@ -429,7 +429,9 @@
     /* Packet receive task */
 
     err = sys_sem_new(&RxReadySem, 0);
-    if(err != ERR_OK) LWIP_ASSERT("RxReadySem creation error", (err == ERR_OK));
+    if(err != ERR_OK) {
+        LWIP_ASSERT("RxReadySem creation error", (err == ERR_OK));
+    }
 	// In GCC code, DEFAULT_THREAD_STACKSIZE 512 bytes is not enough for rx_task
 #if defined (__GNUC__)	
     // mbed OS 2.0, DEFAULT_THREAD_STACKSIZE*3
diff --git a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha_alt_hw.c b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha_alt_hw.c
index 3ce29e2..3b5c657 100644
--- a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha_alt_hw.c
+++ b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha_alt_hw.c
@@ -323,8 +323,8 @@
     int rmn = ilen;
     uint32_t sha_ctl_start = (CRPT->HMAC_CTL & ~(CRPT_HMAC_CTL_DMALAST_Msk | CRPT_HMAC_CTL_DMAEN_Msk | CRPT_HMAC_CTL_HMACEN_Msk)) | CRPT_HMAC_CTL_START_Msk;
     uint32_t sha_opmode = (CRPT->HMAC_CTL & CRPT_HMAC_CTL_OPMODE_Msk) >> CRPT_HMAC_CTL_OPMODE_Pos;
-    uint32_t DGST0_old, DGST1_old, DGST2_old, DGST3_old, DGST4_old, DGST5_old, DGST6_old, DGST7_old,
-        DGST8_old, DGST9_old, DGST10_old, DGST11_old, DGST12_old, DGST13_old, DGST14_old, DGST15_old;
+    uint32_t DGST0_old = 0, DGST1_old = 0, DGST2_old = 0, DGST3_old = 0, DGST4_old = 0, DGST5_old = 0, DGST6_old = 0, DGST7_old = 0,
+        DGST8_old = 0, DGST9_old = 0, DGST10_old = 0, DGST11_old = 0, DGST12_old = 0, DGST13_old = 0, DGST14_old = 0, DGST15_old = 0;
     
     while (rmn > 0) {
         CRPT->HMAC_CTL = sha_ctl_start;
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/TARGET_NUMAKER_PFM_M487/objects.h b/targets/TARGET_NUVOTON/TARGET_M480/TARGET_NUMAKER_PFM_M487/objects.h
index 847dc56..fef01cf 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/TARGET_NUMAKER_PFM_M487/objects.h
+++ b/targets/TARGET_NUVOTON/TARGET_M480/TARGET_NUMAKER_PFM_M487/objects.h
@@ -128,7 +128,7 @@
 
 struct can_s {
     CANName can;
-    char index; 
+    int index; 
 };
 #ifdef __cplusplus
 }
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/analogin_api.c b/targets/TARGET_NUVOTON/TARGET_M480/analogin_api.c
index 988193e..5be190d 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/analogin_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/analogin_api.c
@@ -51,7 +51,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->adc, adc_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->adc);
+    MBED_ASSERT(modinit->modname == (int) obj->adc);
 
     EADC_T *eadc_base = (EADC_T *) NU_MODBASE(obj->adc);
 
@@ -86,7 +86,7 @@
     uint32_t chn =  NU_MODSUBINDEX(obj->adc);
 
     EADC_START_CONV(eadc_base, 1 << chn);
-    while (EADC_GET_DATA_VALID_FLAG(eadc_base, 1 << chn) != (1 << chn));
+    while (EADC_GET_DATA_VALID_FLAG(eadc_base, 1 << chn) != ((uint32_t) (1 << chn)));
     uint16_t conv_res_12 = EADC_GET_CONV_DATA(eadc_base, chn);
     // Just 12 bits are effective. Convert to 16 bits.
     // conv_res_12: 0000 b11b10b9b8 b7b6b5b4 b3b2b1b0
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/can_api.c b/targets/TARGET_NUVOTON/TARGET_M480/can_api.c
index 9e6c9f2..ee5fde7 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/can_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/can_api.c
@@ -57,7 +57,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->can, can_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->can);
+    MBED_ASSERT(modinit->modname == (int) obj->can);
 
     // Reset this module
     SYS_ResetModule(modinit->rsetidx);
@@ -97,7 +97,7 @@
     const struct nu_modinit_s *modinit = get_modinit(obj->can, can_modinit_tab);
 
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->can);
+    MBED_ASSERT(modinit->modname == (int) obj->can);
 
     // Reset this module
     SYS_ResetModule(modinit->rsetidx);
@@ -328,7 +328,7 @@
     const struct nu_modinit_s *modinit = get_modinit(obj->can, can_modinit_tab);
 
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->can);
+    MBED_ASSERT(modinit->modname == (int) obj->can);
 
     // Reset this module
     SYS_ResetModule(modinit->rsetidx);
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_can.c b/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_can.c
index f0b818a..539c1f1 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_can.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_can.c
@@ -610,18 +610,18 @@
 static int can_update_spt(int sampl_pt, int tseg, int *tseg1, int *tseg2)
 {
     *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
-    if (*tseg2 < TSEG2_MIN) {
+    if (*tseg2 < ((int) TSEG2_MIN)) {
         *tseg2 = TSEG2_MIN;
     } else {
     }
 
-    if (*tseg2 > TSEG2_MAX) {
+    if (*tseg2 > ((int) TSEG2_MAX)) {
         *tseg2 = TSEG2_MAX;
     } else {
     }
 
     *tseg1 = tseg - *tseg2;
-    if (*tseg1 > TSEG1_MAX) {
+    if (*tseg1 > ((int) TSEG1_MAX)) {
         *tseg1 = TSEG1_MAX;
         *tseg2 = tseg - *tseg1;
     } else {
@@ -679,14 +679,14 @@
     }
 
     /* tseg even = round down, odd = round up */
-    for (tseg = (TSEG1_MAX + TSEG2_MAX) * 2ul + 1ul; tseg >= (TSEG1_MIN + TSEG2_MIN) * 2ul; tseg--) {
+    for (tseg = (TSEG1_MAX + TSEG2_MAX) * 2ul + 1ul; tseg >= (int) ((TSEG1_MIN + TSEG2_MIN) * 2ul); tseg--) {
         tsegall = 1ul + tseg / 2ul;
         /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
         brp = clock_freq / (tsegall * u32BaudRate) + tseg % 2;
         /* chose brp step which is possible in system */
         brp = (brp / BRP_INC) * BRP_INC;
 
-        if ((brp < BRP_MIN) || (brp > BRP_MAX)) {
+        if ((brp < ((int) BRP_MIN)) || (brp > ((int) BRP_MAX))) {
             continue;
         }
         rate = clock_freq / (brp * tsegall);
@@ -728,7 +728,7 @@
         sjw = SJW_MAX;
     }
     /* bt->sjw must not be higher than tseg2 */
-    if (tseg2 < sjw) {
+    if (tseg2 < ((int) sjw)) {
         sjw = tseg2;
     }
 
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_i2s.c b/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_i2s.c
index b5afbeb..c60a2f1 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_i2s.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_i2s.c
@@ -198,7 +198,7 @@
   */
 void I2S_SetFIFO(I2S_T *i2s, uint32_t u32TxThreshold, uint32_t u32RxThreshold)
 {
-    i2s->CTL1 = (i2s->CTL1 & ~(I2S_CTL1_TXTH_Msk | I2S_CTL1_RXTH_Msk) |
+    i2s->CTL1 = ((i2s->CTL1 & ~(I2S_CTL1_TXTH_Msk | I2S_CTL1_RXTH_Msk)) |
                  (u32TxThreshold << I2S_CTL1_TXTH_Pos) |
                  (u32RxThreshold << I2S_CTL1_RXTH_Pos));
 }
@@ -225,7 +225,7 @@
   */
 void I2S_ConfigureTDM(I2S_T *i2s, uint32_t u32ChannelWidth, uint32_t u32ChannelNum, uint32_t u32SyncWidth)
 {
-    i2s->CTL0 = (i2s->CTL0 & ~(I2S_CTL0_TDMCHNUM_Msk | I2S_CTL0_CHWIDTH_Msk | I2S_CTL0_PCMSYNC_Msk) |
+    i2s->CTL0 = ((i2s->CTL0 & ~(I2S_CTL0_TDMCHNUM_Msk | I2S_CTL0_CHWIDTH_Msk | I2S_CTL0_PCMSYNC_Msk)) |
                  (u32ChannelWidth << I2S_CTL0_CHWIDTH_Pos) |
                  (u32ChannelNum << I2S_CTL0_TDMCHNUM_Pos) |
                  (u32SyncWidth << I2S_CTL0_PCMSYNC_Pos));
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_sdh.c b/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_sdh.c
index 74e3168..7c83636 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_sdh.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_sdh.c
@@ -360,7 +360,7 @@
 {
     uint32_t volatile i, status;
     unsigned int resp;
-    unsigned int CIDBuffer[4];
+    uint32_t CIDBuffer[4];
     uint32_t volatile u32CmdTimeOut;
     SDH_INFO_T *pSD;
 
@@ -630,7 +630,7 @@
 void SDH_Get_SD_info(SDH_T *sdh)
 {
     unsigned int R_LEN, C_Size, MULT, size;
-    unsigned int Buffer[4];
+    uint32_t Buffer[4];
     unsigned char *ptr;
     SDH_INFO_T *pSD;
 
@@ -796,7 +796,7 @@
  */
 uint32_t SDH_Read(SDH_T *sdh, uint8_t *pu8BufAddr, uint32_t u32StartSec, uint32_t u32SecCount)
 {
-    uint32_t volatile bIsSendCmd = FALSE, buf;
+    uint32_t volatile bIsSendCmd = FALSE;
     uint32_t volatile reg;
     uint32_t volatile i, loop, status;
     uint32_t blksize = SDH_BLOCK_SIZE;
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_spim.c b/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_spim.c
index 8ef183b..c41caeb 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_spim.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/device/StdDriver/m480_spim.c
@@ -289,7 +289,7 @@
     SwitchNBitOutput(u32NBit);
     spim_write(cmdBuf, sizeof (cmdBuf));
     SwitchNBitInput(u32NBit);
-    spim_read(dataBuf, sizeof (dataBuf));
+    spim_read(dataBuf, u32NRx);
     SPIM_SET_SS_EN(0);                          /* CS deactivated.  */
 }
 
@@ -349,7 +349,7 @@
     SwitchNBitOutput(u32NBit);
     spim_write(cmdBuf, sizeof (cmdBuf));
     SwitchNBitInput(u32NBit);
-    spim_read(dataBuf, sizeof (dataBuf));
+    spim_read(dataBuf, u32NRx);
     SPIM_SET_SS_EN(0);                          /* CS deactivated. */
 }
 
@@ -388,7 +388,7 @@
     SwitchNBitOutput(u32NBit);
     spim_write(cmdBuf, sizeof (cmdBuf));
     SwitchNBitInput(u32NBit);
-    spim_read(dataBuf, sizeof (dataBuf));
+    spim_read(dataBuf, u32NRx);
     SPIM_SET_SS_EN(0);                          /* CS deactivated. */
 }
 
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/i2c_api.c b/targets/TARGET_NUVOTON/TARGET_M480/i2c_api.c
index e635693..2313d4f 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/i2c_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/i2c_api.c
@@ -100,7 +100,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->i2c.i2c, i2c_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->i2c.i2c);
+    MBED_ASSERT(modinit->modname == (int) obj->i2c.i2c);
 
     // Reset this module
     SYS_ResetModule(modinit->rsetidx);
@@ -881,7 +881,7 @@
 {
     const struct nu_modinit_s *modinit = get_modinit(obj->i2c.i2c, i2c_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->i2c.i2c);
+    MBED_ASSERT(modinit->modname == (int) obj->i2c.i2c);
 
     // Vector will be changed for async transfer. Use it to judge if async transfer is on-going.
     uint32_t vec = NVIC_GetVector(modinit->irq_n);
@@ -909,7 +909,7 @@
 {
     const struct nu_modinit_s *modinit = get_modinit(obj->i2c.i2c, i2c_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->i2c.i2c);
+    MBED_ASSERT(modinit->modname == (int) obj->i2c.i2c);
 
     if (enable) {
         NVIC_SetVector(modinit->irq_n, handler);
@@ -924,7 +924,7 @@
 {
     const struct nu_modinit_s *modinit = get_modinit(obj->i2c.i2c, i2c_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->i2c.i2c);
+    MBED_ASSERT(modinit->modname == (int) obj->i2c.i2c);
 
     struct nu_i2c_var *var = (struct nu_i2c_var *) modinit->var;
     i2c_enable_vector_interrupt(obj, (uint32_t) var->vec, 1);
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c b/targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c
index 15b7df4..93bfe68 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c
@@ -66,7 +66,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->pwm, pwm_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->pwm);
+    MBED_ASSERT(modinit->modname == (int) obj->pwm);
 
     // NOTE: All channels (identified by PWMName) share a PWM module. This reset will also affect other channels of the same PWM module.
     if (! ((struct nu_pwm_var *) modinit->var)->en_msk) {
@@ -107,7 +107,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->pwm, pwm_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->pwm);
+    MBED_ASSERT(modinit->modname == (int) obj->pwm);
     ((struct nu_pwm_var *) modinit->var)->en_msk &= ~(1 << chn);
 
 
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/spi_api.c b/targets/TARGET_NUVOTON/TARGET_M480/spi_api.c
index 87f1daa..88ae09d 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/spi_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/spi_api.c
@@ -116,7 +116,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    MBED_ASSERT(modinit->modname == (int) obj->spi.spi);
 
     // Reset this module
     SYS_ResetModule(modinit->rsetidx);
@@ -166,7 +166,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    MBED_ASSERT(modinit->modname == (int) obj->spi.spi);
 
     SPI_DisableInt(((SPI_T *) NU_MODBASE(obj->spi.spi)), (SPI_FIFO_RXOV_INT_MASK | SPI_FIFO_RXTH_INT_MASK | SPI_FIFO_TXTH_INT_MASK));
     NVIC_DisableIRQ(modinit->irq_n);
@@ -331,7 +331,7 @@
         // DMA way
         const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
         MBED_ASSERT(modinit != NULL);
-        MBED_ASSERT(modinit->modname == obj->spi.spi);
+        MBED_ASSERT(modinit->modname == (int) obj->spi.spi);
 
         PDMA_T *pdma_base = dma_modbase();
 
@@ -504,7 +504,7 @@
 {
     const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    MBED_ASSERT(modinit->modname == (int) obj->spi.spi);
 
     if (enable) {
         NVIC_SetVector(modinit->irq_n, handler);
@@ -741,7 +741,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    MBED_ASSERT(modinit->modname == (int) obj->spi.spi);
 
     void (*vec)(void) = (void (*)(void)) NVIC_GetVector(modinit->irq_n);
     vec();
@@ -764,7 +764,7 @@
 
     const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    MBED_ASSERT(modinit->modname == (int) obj->spi.spi);
 
     void (*vec)(void) = (void (*)(void)) NVIC_GetVector(modinit->irq_n);
     vec();
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/trng_api.c b/targets/TARGET_NUVOTON/TARGET_M480/trng_api.c
index 781bb78..4f3c6ef 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/trng_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/trng_api.c
@@ -85,7 +85,7 @@
         memcpy(output, &tmpBuff, length);
         *output_length = length;
     } else {
-        for (int i = 0; i < (length/32); i++) {
+        for (unsigned i = 0; i < (length/32); i++) {
             trng_get(output);
             *output_length += 32;
             output += 32;
diff --git a/targets/TARGET_NUVOTON/nu_modutil.c b/targets/TARGET_NUVOTON/nu_modutil.c
index aeccb46..2743996 100644
--- a/targets/TARGET_NUVOTON/nu_modutil.c
+++ b/targets/TARGET_NUVOTON/nu_modutil.c
@@ -23,7 +23,7 @@
     MBED_ASSERT(modprop_tab != NULL);
     const struct nu_modinit_s *modprop_ind = modprop_tab;
     while (modprop_ind->modname != NC) {
-        if (modname == modprop_ind->modname) {
+        if ((int) modname == modprop_ind->modname) {
             return modprop_ind;
         }
         else {