diff --git a/targets/TARGET_NUVOTON/TARGET_M451/TARGET_NUMAKER_PFM_M453/objects.h b/targets/TARGET_NUVOTON/TARGET_M451/TARGET_NUMAKER_PFM_M453/objects.h
index 6744a32ce9..9c633835d9 100644
--- a/targets/TARGET_NUVOTON/TARGET_M451/TARGET_NUMAKER_PFM_M453/objects.h
+++ b/targets/TARGET_NUVOTON/TARGET_M451/TARGET_NUMAKER_PFM_M453/objects.h
@@ -117,10 +117,6 @@ struct pwmout_s {
     uint32_t pulsewidth_us;
 };
 
-struct sleep_s {
-    int powerdown;
-};
-
 struct can_s {
     CANName can;
     char index; 
diff --git a/targets/TARGET_NUVOTON/TARGET_M451/i2c_api.c b/targets/TARGET_NUVOTON/TARGET_M451/i2c_api.c
index 8b05fe8627..7f918418cd 100644
--- a/targets/TARGET_NUVOTON/TARGET_M451/i2c_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M451/i2c_api.c
@@ -339,25 +339,6 @@ static int i2c_set_int(i2c_t *obj, int inten)
     return inten_back;
 }
 
-int i2c_allow_powerdown(void)
-{
-    uint32_t modinit_mask = i2c_modinit_mask;
-    while (modinit_mask) {
-        int i2c_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = i2c_modinit_tab + i2c_idx;
-        struct nu_i2c_var *var = (struct nu_i2c_var *) modinit->var;
-        if (var->obj) {
-            // Disallow entering power-down mode if I2C transfer is enabled.
-            if (i2c_active(var->obj)) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << i2c_idx);
-    }
-    
-    return 1;
-}
-
 static int i2c_do_tran(i2c_t *obj, char *buf, int length, int read, int naklastdata)
 {
     if (! buf || ! length) {
diff --git a/targets/TARGET_NUVOTON/TARGET_M451/pwmout_api.c b/targets/TARGET_NUVOTON/TARGET_M451/pwmout_api.c
index f89dc4f6a0..d95197c3e4 100644
--- a/targets/TARGET_NUVOTON/TARGET_M451/pwmout_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M451/pwmout_api.c
@@ -172,26 +172,6 @@ void pwmout_pulsewidth_us(pwmout_t* obj, int us)
     pwmout_config(obj);
 }
 
-int pwmout_allow_powerdown(void)
-{
-    uint32_t modinit_mask = pwm_modinit_mask;
-    while (modinit_mask) {
-        int pwm_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = pwm_modinit_tab + pwm_idx;
-        if (modinit->modname != NC) {
-            PWM_T *pwm_base = (PWM_T *) NU_MODBASE(modinit->modname);
-            uint32_t chn = NU_MODSUBINDEX(modinit->modname);
-            // Disallow entering power-down mode if PWM counter is enabled.
-            if ((pwm_base->CNTEN & (1 << chn)) && pwm_base->CMPDAT[chn]) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << pwm_idx);
-    }
-    
-    return 1;
-}
-
 static void pwmout_config(pwmout_t* obj)
 {
     PWM_T *pwm_base = (PWM_T *) NU_MODBASE(obj->pwm);
diff --git a/targets/TARGET_NUVOTON/TARGET_M451/serial_api.c b/targets/TARGET_NUVOTON/TARGET_M451/serial_api.c
index b0965477c7..382ea3e7e7 100644
--- a/targets/TARGET_NUVOTON/TARGET_M451/serial_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M451/serial_api.c
@@ -656,33 +656,6 @@ int serial_irq_handler_asynch(serial_t *obj)
     return (obj->serial.event & (event_rx | event_tx));
 }
 
-int serial_allow_powerdown(void)
-{
-    uint32_t modinit_mask = uart_modinit_mask;
-    while (modinit_mask) {
-        int uart_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = uart_modinit_tab + uart_idx;
-        if (modinit->modname != NC) {
-            UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
-            // Disallow entering power-down mode if Tx FIFO has data to flush
-            if (! UART_IS_TX_EMPTY((uart_base))) {
-                return 0;
-            }
-            // Disallow entering power-down mode if async Rx transfer (not PDMA) is on-going
-            if (uart_base->INTEN & (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk)) {
-                return 0;
-            }
-            // Disallow entering power-down mode if async Rx transfer (PDMA) is on-going
-            if (uart_base->INTEN & UART_INTEN_RXPDMAEN_Msk) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << uart_idx);
-    }
-    
-    return 1;
-}
-
 static void uart0_vec_async(void)
 {
     uart_irq_async(uart0_var.obj);
diff --git a/targets/TARGET_NUVOTON/TARGET_M451/spi_api.c b/targets/TARGET_NUVOTON/TARGET_M451/spi_api.c
index 5616bd60cc..5d035ccf99 100644
--- a/targets/TARGET_NUVOTON/TARGET_M451/spi_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M451/spi_api.c
@@ -470,25 +470,6 @@ uint8_t spi_active(spi_t *obj)
     return (spi_base->CTL & SPI_CTL_SPIEN_Msk);
 }
 
-int spi_allow_powerdown(void)
-{
-    uint32_t modinit_mask = spi_modinit_mask;
-    while (modinit_mask) {
-        int spi_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = spi_modinit_tab + spi_idx;
-        if (modinit->modname != NC) {
-            SPI_T *spi_base = (SPI_T *) NU_MODBASE(modinit->modname);
-            // Disallow entering power-down mode if SPI transfer is enabled.
-            if (spi_base->CTL & SPI_CTL_SPIEN_Msk) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << spi_idx);
-    }
-    
-    return 1;
-}
-
 static int spi_writeable(spi_t * obj)
 {
     // Receive FIFO must not be full to avoid receive FIFO overflow on next transmit/receive
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 fef01cfdaf..e3d24534d8 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
@@ -118,10 +118,6 @@ struct pwmout_s {
     uint32_t pulsewidth_us;
 };
 
-struct sleep_s {
-    int powerdown;
-};
-
 struct trng_s {
     uint8_t dummy;
 };
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/i2c_api.c b/targets/TARGET_NUVOTON/TARGET_M480/i2c_api.c
index 2313d4f928..bf8e92a87c 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/i2c_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/i2c_api.c
@@ -330,25 +330,6 @@ static int i2c_set_int(i2c_t *obj, int inten)
     return inten_back;
 }
 
-int i2c_allow_powerdown(void)
-{
-    uint32_t modinit_mask = i2c_modinit_mask;
-    while (modinit_mask) {
-        int i2c_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = i2c_modinit_tab + i2c_idx;
-        struct nu_i2c_var *var = (struct nu_i2c_var *) modinit->var;
-        if (var->obj) {
-            // Disallow entering power-down mode if I2C transfer is enabled.
-            if (i2c_active(var->obj)) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << i2c_idx);
-    }
-
-    return 1;
-}
-
 static int i2c_do_tran(i2c_t *obj, char *buf, int length, int read, int naklastdata)
 {
     if (! buf || ! length) {
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c b/targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c
index 93bfe68116..12d4987256 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c
@@ -167,26 +167,6 @@ void pwmout_pulsewidth_us(pwmout_t* obj, int us)
     pwmout_config(obj, 1);
 }
 
-int pwmout_allow_powerdown(void)
-{
-    uint32_t modinit_mask = pwm_modinit_mask;
-    while (modinit_mask) {
-        int pwm_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = pwm_modinit_tab + pwm_idx;
-        if (modinit->modname != NC) {
-            EPWM_T *pwm_base = (EPWM_T *) NU_MODBASE(modinit->modname);
-            uint32_t chn = NU_MODSUBINDEX(modinit->modname);
-            // Disallow entering power-down mode if PWM counter is enabled.
-            if ((pwm_base->CNTEN & (1 << chn)) && pwm_base->CMPDAT[chn]) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << pwm_idx);
-    }
-
-    return 1;
-}
-
 static void pwmout_config(pwmout_t* obj, int start)
 {
     EPWM_T *pwm_base = (EPWM_T *) NU_MODBASE(obj->pwm);
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/serial_api.c b/targets/TARGET_NUVOTON/TARGET_M480/serial_api.c
index e45867c118..25695156a3 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/serial_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/serial_api.c
@@ -710,33 +710,6 @@ int serial_irq_handler_asynch(serial_t *obj)
     return (obj->serial.event & (event_rx | event_tx));
 }
 
-int serial_allow_powerdown(void)
-{
-    uint32_t modinit_mask = uart_modinit_mask;
-    while (modinit_mask) {
-        int uart_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = uart_modinit_tab + uart_idx;
-        if (modinit->modname != NC) {
-            UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
-            // Disallow entering power-down mode if Tx FIFO has data to flush
-            if (! UART_IS_TX_EMPTY((uart_base))) {
-                return 0;
-            }
-            // Disallow entering power-down mode if async Rx transfer (not PDMA) is on-going
-            if (uart_base->INTEN & (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk)) {
-                return 0;
-            }
-            // Disallow entering power-down mode if async Rx transfer (PDMA) is on-going
-            if (uart_base->INTEN & UART_INTEN_RXPDMAEN_Msk) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << uart_idx);
-    }
-
-    return 1;
-}
-
 static void uart0_vec_async(void)
 {
     uart_irq_async(uart0_var.obj);
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/spi_api.c b/targets/TARGET_NUVOTON/TARGET_M480/spi_api.c
index 88ae09d6ff..79e6818d28 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/spi_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/spi_api.c
@@ -461,25 +461,6 @@ uint8_t spi_active(spi_t *obj)
     return (spi_base->CTL & SPI_CTL_SPIEN_Msk);
 }
 
-int spi_allow_powerdown(void)
-{
-    uint32_t modinit_mask = spi_modinit_mask;
-    while (modinit_mask) {
-        int spi_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = spi_modinit_tab + spi_idx;
-        if (modinit->modname != NC) {
-            SPI_T *spi_base = (SPI_T *) NU_MODBASE(modinit->modname);
-            // Disallow entering power-down mode if SPI transfer is enabled.
-            if (spi_base->CTL & SPI_CTL_SPIEN_Msk) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << spi_idx);
-    }
-
-    return 1;
-}
-
 static int spi_writeable(spi_t * obj)
 {
     // Receive FIFO must not be full to avoid receive FIFO overflow on next transmit/receive
diff --git a/targets/TARGET_NUVOTON/TARGET_NANO100/TARGET_NUMAKER_PFM_NANO130/objects.h b/targets/TARGET_NUVOTON/TARGET_NANO100/TARGET_NUMAKER_PFM_NANO130/objects.h
index 8ec51b38e8..12476fd7c1 100644
--- a/targets/TARGET_NUVOTON/TARGET_NANO100/TARGET_NUMAKER_PFM_NANO130/objects.h
+++ b/targets/TARGET_NUVOTON/TARGET_NANO100/TARGET_NUMAKER_PFM_NANO130/objects.h
@@ -110,9 +110,6 @@ struct pwmout_s {
     uint32_t pulsewidth_us;
 };
 
-struct sleep_s {
-    int powerdown;
-};
 #ifdef __cplusplus
 }
 #endif
diff --git a/targets/TARGET_NUVOTON/TARGET_NANO100/i2c_api.c b/targets/TARGET_NUVOTON/TARGET_NANO100/i2c_api.c
index 375602b461..3e146ee8b1 100644
--- a/targets/TARGET_NUVOTON/TARGET_NANO100/i2c_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_NANO100/i2c_api.c
@@ -358,25 +358,6 @@ static int i2c_set_int(i2c_t *obj, int inten)
     return inten_back;
 }
 
-int i2c_allow_powerdown(void)
-{
-    uint32_t modinit_mask = i2c_modinit_mask;
-    while (modinit_mask) {
-        int i2c_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = i2c_modinit_tab + i2c_idx;
-        struct nu_i2c_var *var = (struct nu_i2c_var *) modinit->var;
-        if (var->obj) {
-            // Disallow entering power-down mode if I2C transfer is enabled.
-            if (i2c_active(var->obj)) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << i2c_idx);
-    }
-    
-    return 1;
-}
-
 static int i2c_do_tran(i2c_t *obj, char *buf, int length, int read, int naklastdata)
 {
     if (! buf || ! length) {
diff --git a/targets/TARGET_NUVOTON/TARGET_NANO100/pwmout_api.c b/targets/TARGET_NUVOTON/TARGET_NANO100/pwmout_api.c
index eb64849207..7eca1a1ab3 100644
--- a/targets/TARGET_NUVOTON/TARGET_NANO100/pwmout_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_NANO100/pwmout_api.c
@@ -176,26 +176,6 @@ void pwmout_pulsewidth_us(pwmout_t* obj, int us)
     pwmout_config(obj);
 }
 
-int pwmout_allow_powerdown(void)
-{
-    uint32_t modinit_mask = pwm_modinit_mask;
-    while (modinit_mask) {
-        int pwm_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = pwm_modinit_tab + pwm_idx;
-        if (modinit->modname != NC) {
-            PWM_T *pwm_base = (PWM_T *) NU_MODBASE(modinit->modname);
-            uint32_t chn = NU_MODSUBINDEX(modinit->modname);
-            // Disallow entering power-down mode if PWM counter is enabled.
-            if (pwm_base->OE & (1 << chn)) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << pwm_idx);
-    }
-    
-    return 1;
-}
-
 static void pwmout_config(pwmout_t* obj)
 {
     PWM_T *pwm_base = (PWM_T *) NU_MODBASE(obj->pwm);
diff --git a/targets/TARGET_NUVOTON/TARGET_NANO100/serial_api.c b/targets/TARGET_NUVOTON/TARGET_NANO100/serial_api.c
index 93f9146751..7810d00977 100644
--- a/targets/TARGET_NUVOTON/TARGET_NANO100/serial_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_NANO100/serial_api.c
@@ -597,33 +597,6 @@ int serial_irq_handler_asynch(serial_t *obj)
     return (obj->serial.event & (event_rx | event_tx));
 }
 
-int serial_allow_powerdown(void)
-{
-    uint32_t modinit_mask = uart_modinit_mask;
-    while (modinit_mask) {
-        int uart_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = uart_modinit_tab + uart_idx;
-        if (modinit->modname != NC) {
-            UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
-            // Disallow entering power-down mode if Tx FIFO has data to flush
-            if (! UART_IS_TX_EMPTY((uart_base))) {
-                return 0;
-            }
-            // Disallow entering power-down mode if async Rx transfer (not PDMA) is on-going
-            if (uart_base->IER & (UART_IER_RDA_IE_Msk | UART_IER_RTO_IE_Msk)) {
-                return 0;
-            }
-            // Disallow entering power-down mode if async Rx transfer (PDMA) is on-going
-            if (uart_base->CTL & UART_CTL_DMA_RX_EN_Msk) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << uart_idx);
-    }
-    
-    return 1;
-}
-
 static void uart_irq_async(serial_t *obj)
 {
     if (serial_is_irq_en(obj, RxIrq)) {
diff --git a/targets/TARGET_NUVOTON/TARGET_NANO100/spi_api.c b/targets/TARGET_NUVOTON/TARGET_NANO100/spi_api.c
index 86def36d76..0bc47ae67f 100644
--- a/targets/TARGET_NUVOTON/TARGET_NANO100/spi_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_NANO100/spi_api.c
@@ -505,24 +505,6 @@ uint8_t spi_active(spi_t *obj)
     return SPI_IS_BUSY(spi_base);
 }
 
-int spi_allow_powerdown(void)
-{
-    uint32_t modinit_mask = spi_modinit_mask;
-    while (modinit_mask) {
-        int spi_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = spi_modinit_tab + spi_idx;
-        if (modinit->modname != NC) {
-            SPI_T *spi_base = (SPI_T *) NU_MODBASE(modinit->modname);
-            if (SPI_IS_BUSY(spi_base)) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << spi_idx);
-    }
-    
-    return 1;
-}
-
 void SPI0_IRQHandler(void)
 {
     spi_irq(spi0_var.obj);
diff --git a/targets/TARGET_NUVOTON/TARGET_NUC472/TARGET_NUMAKER_PFM_NUC472/objects.h b/targets/TARGET_NUVOTON/TARGET_NUC472/TARGET_NUMAKER_PFM_NUC472/objects.h
index 2e62f15efc..da3db2d54b 100644
--- a/targets/TARGET_NUVOTON/TARGET_NUC472/TARGET_NUMAKER_PFM_NUC472/objects.h
+++ b/targets/TARGET_NUVOTON/TARGET_NUC472/TARGET_NUMAKER_PFM_NUC472/objects.h
@@ -118,10 +118,6 @@ struct pwmout_s {
     uint32_t pulsewidth_us;
 };
 
-struct sleep_s {
-    int powerdown;
-};
-
 struct trng_s {
     uint8_t dummy;
 };
diff --git a/targets/TARGET_NUVOTON/TARGET_NUC472/i2c_api.c b/targets/TARGET_NUVOTON/TARGET_NUC472/i2c_api.c
index 481f7d6bd0..450451d89f 100644
--- a/targets/TARGET_NUVOTON/TARGET_NUC472/i2c_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_NUC472/i2c_api.c
@@ -356,25 +356,6 @@ static int i2c_set_int(i2c_t *obj, int inten)
     return inten_back;
 }
 
-int i2c_allow_powerdown(void)
-{
-    uint32_t modinit_mask = i2c_modinit_mask;
-    while (modinit_mask) {
-        int i2c_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = i2c_modinit_tab + i2c_idx;
-        struct nu_i2c_var *var = (struct nu_i2c_var *) modinit->var;
-        if (var->obj) {
-            // Disallow entering power-down mode if I2C transfer is enabled.
-            if (i2c_active(var->obj)) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << i2c_idx);
-    }
-    
-    return 1;
-}
-
 static int i2c_do_tran(i2c_t *obj, char *buf, int length, int read, int naklastdata)
 {
     if (! buf || ! length) {
diff --git a/targets/TARGET_NUVOTON/TARGET_NUC472/pwmout_api.c b/targets/TARGET_NUVOTON/TARGET_NUC472/pwmout_api.c
index 90165697c6..bd2409ff8c 100644
--- a/targets/TARGET_NUVOTON/TARGET_NUC472/pwmout_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_NUC472/pwmout_api.c
@@ -195,26 +195,6 @@ void pwmout_pulsewidth_us(pwmout_t* obj, int us)
     pwmout_config(obj);
 }
 
-int pwmout_allow_powerdown(void)
-{
-    uint32_t modinit_mask = pwm_modinit_mask;
-    while (modinit_mask) {
-        int pwm_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = pwm_modinit_tab + pwm_idx;
-        if (modinit->modname != NC) {
-            PWM_T *pwm_base = (PWM_T *) NU_MODBASE(modinit->modname);
-            uint32_t chn = NU_MODSUBINDEX(modinit->modname);
-            // Disallow entering power-down mode if PWM counter is enabled.
-            if ((pwm_base->CNTEN & (1 << chn)) && pwm_base->CMPDAT[chn]) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << pwm_idx);
-    }
-    
-    return 1;
-}
-
 static void pwmout_config(pwmout_t* obj)
 {
     PWM_T *pwm_base = (PWM_T *) NU_MODBASE(obj->pwm);
diff --git a/targets/TARGET_NUVOTON/TARGET_NUC472/serial_api.c b/targets/TARGET_NUVOTON/TARGET_NUC472/serial_api.c
index b3dd9737aa..be8e304c4e 100644
--- a/targets/TARGET_NUVOTON/TARGET_NUC472/serial_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_NUC472/serial_api.c
@@ -694,33 +694,6 @@ int serial_irq_handler_asynch(serial_t *obj)
     return (obj->serial.event & (event_rx | event_tx));
 }
 
-int serial_allow_powerdown(void)
-{
-    uint32_t modinit_mask = uart_modinit_mask;
-    while (modinit_mask) {
-        int uart_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = uart_modinit_tab + uart_idx;
-        if (modinit->modname != NC) {
-            UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
-            // Disallow entering power-down mode if Tx FIFO has data to flush
-            if (! UART_IS_TX_EMPTY((uart_base))) {
-                return 0;
-            }
-            // Disallow entering power-down mode if async Rx transfer (not PDMA) is on-going
-            if (uart_base->INTEN & (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk)) {
-                return 0;
-            }
-            // Disallow entering power-down mode if async Rx transfer (PDMA) is on-going
-            if (uart_base->INTEN & UART_INTEN_RXPDMAEN_Msk) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << uart_idx);
-    }
-    
-    return 1;
-}
-
 static void uart0_vec_async(void)
 {
     uart_irq_async(uart0_var.obj);
diff --git a/targets/TARGET_NUVOTON/TARGET_NUC472/spi_api.c b/targets/TARGET_NUVOTON/TARGET_NUC472/spi_api.c
index 6b12a925f2..1ab0704fc2 100644
--- a/targets/TARGET_NUVOTON/TARGET_NUC472/spi_api.c
+++ b/targets/TARGET_NUVOTON/TARGET_NUC472/spi_api.c
@@ -469,25 +469,6 @@ uint8_t spi_active(spi_t *obj)
     return (spi_base->CTL & SPI_CTL_SPIEN_Msk);
 }
 
-int spi_allow_powerdown(void)
-{
-    uint32_t modinit_mask = spi_modinit_mask;
-    while (modinit_mask) {
-        int spi_idx = nu_ctz(modinit_mask);
-        const struct nu_modinit_s *modinit = spi_modinit_tab + spi_idx;
-        if (modinit->modname != NC) {
-            SPI_T *spi_base = (SPI_T *) NU_MODBASE(modinit->modname);
-            // Disallow entering power-down mode if SPI transfer is enabled.
-            if (spi_base->CTL & SPI_CTL_SPIEN_Msk) {
-                return 0;
-            }
-        }
-        modinit_mask &= ~(1 << spi_idx);
-    }
-    
-    return 1;
-}
-
 static int spi_writeable(spi_t * obj)
 {
     // Receive FIFO must not be full to avoid receive FIFO overflow on next transmit/receive