Merge pull request #8049 from OpenNuvoton/nuvoton_fix_hal_sleep

Nuvoton: Fix mbed_hal-sleep test failed

targets/TARGET_NUVOTON/TARGET_M2351/device/stddriver_secure.c

@@ -197,6 +197,18 @@ void SYS_UnlockReg_S(void)
     SYS_UnlockReg();
 }
 
+__NONSECURE_ENTRY
+void CLK_Idle_S(void)
+{
+    CLK_Idle();
+}
+
+__NONSECURE_ENTRY
+void CLK_PowerDown_S(void)
+{
+    CLK_PowerDown();
+}
+
 static bool check_mod_ns(int modclass, uint32_t modidx)
 {
     const nu_modidx_ns_t *modidx_ns = modidx_ns_tab;

targets/TARGET_NUVOTON/TARGET_M2351/device/stddriver_secure.h

@@ -71,6 +71,14 @@ void SYS_LockReg_S(void);
 __NONSECURE_ENTRY
 void SYS_UnlockReg_S(void);
 
+/* Secure CLK_Idle */
+__NONSECURE_ENTRY
+void CLK_Idle_S(void);
+
+/* Secure CLK_PowerDown */
+__NONSECURE_ENTRY
+void CLK_PowerDown_S(void);
+
 #ifdef __cplusplus
 }
 #endif

targets/TARGET_NUVOTON/TARGET_M2351/lp_ticker.c

@@ -19,9 +19,9 @@
 #if DEVICE_LPTICKER
 
 #include "sleep_api.h"
-#include "mbed_wait_api.h"
 #include "mbed_assert.h"
 #include "nu_modutil.h"
+#include "nu_timer.h"
 #include "nu_miscutil.h"
 #include "partition_M2351.h"
 
@@ -135,10 +135,10 @@ void lp_ticker_init(void)
     // Continuous mode
     // NOTE: TIMER_CTL_CNTDATEN_Msk exists in NUC472, but not in M451/M480/M2351. In M451/M480/M2351, TIMER_CNT is updated continuously by default.
     timer_base->CTL = TIMER_CONTINUOUS_MODE | prescale_timer/* | TIMER_CTL_CNTDATEN_Msk*/;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     timer_base->CMP = cmp_timer;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     // Set vector
     NVIC_SetVector(TIMER_MODINIT.irq_n, (uint32_t) TIMER_MODINIT.var);
@@ -146,13 +146,13 @@ void lp_ticker_init(void)
     NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
 
     TIMER_EnableInt(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_EnableWakeup(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_Start(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     /* Wait for timer to start counting and raise active flag */
     while(! (timer_base->CTL & TIMER_CTL_ACTSTS_Msk));

targets/TARGET_NUVOTON/TARGET_M2351/serial_api.c

@@ -25,6 +25,7 @@
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
 #include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -87,6 +88,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -1171,4 +1174,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_M2351/sleep.c

@@ -22,30 +22,48 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
 
-#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
  */
-__NONSECURE_ENTRY
 void hal_sleep(void)
 {
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
     SYS_UnlockReg();
     CLK_Idle();
     SYS_LockReg();
+#else
+    SYS_UnlockReg_S();
+    CLK_Idle_S();
+    SYS_LockReg_S();
+#endif
 }
 
 /**
  * Enter power-down mode, in which HXT/HIRC are halted.
  */
-__NONSECURE_ENTRY
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
+#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();
+#else
+    SYS_UnlockReg_S();
+    CLK_PowerDown_S();
+    SYS_LockReg_S();
+#endif
 }
 
 #endif
-#endif

targets/TARGET_NUVOTON/TARGET_M451/lp_ticker.c

@@ -19,9 +19,9 @@
 #if DEVICE_LPTICKER
 
 #include "sleep_api.h"
-#include "mbed_wait_api.h"
 #include "mbed_assert.h"
 #include "nu_modutil.h"
+#include "nu_timer.h"
 #include "nu_miscutil.h"
 
 /* Micro seconds per second */
@@ -101,10 +101,10 @@ void lp_ticker_init(void)
     // Continuous mode
     // NOTE: TIMER_CTL_CNTDATEN_Msk exists in NUC472, but not in M451. In M451, TIMER_CNT is updated continuously by default.
     timer_base->CTL = TIMER_CONTINUOUS_MODE | prescale_timer/* | TIMER_CTL_CNTDATEN_Msk*/;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     timer_base->CMP = cmp_timer;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     // Set vector
     NVIC_SetVector(TIMER_MODINIT.irq_n, (uint32_t) TIMER_MODINIT.var);
@@ -112,13 +112,13 @@ void lp_ticker_init(void)
     NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
 
     TIMER_EnableInt(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_EnableWakeup(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_Start(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     /* Wait for timer to start counting and raise active flag */
     while(! (timer_base->CTL & TIMER_CTL_ACTSTS_Msk));

targets/TARGET_NUVOTON/TARGET_M451/serial_api.c

@@ -25,6 +25,7 @@
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
 #include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -83,6 +84,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -1088,4 +1091,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_M451/sleep.c

@@ -22,6 +22,11 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
+
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
@@ -38,6 +43,12 @@ void hal_sleep(void)
  */
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();

targets/TARGET_NUVOTON/TARGET_M480/lp_ticker.c

@@ -19,9 +19,9 @@
 #if DEVICE_LPTICKER
 
 #include "sleep_api.h"
-#include "mbed_wait_api.h"
 #include "mbed_assert.h"
 #include "nu_modutil.h"
+#include "nu_timer.h"
 #include "nu_miscutil.h"
 
 /* Micro seconds per second */
@@ -101,10 +101,10 @@ void lp_ticker_init(void)
     // Continuous mode
     // NOTE: TIMER_CTL_CNTDATEN_Msk exists in NUC472, but not in M451/M480. In M451/M480, TIMER_CNT is updated continuously by default.
     timer_base->CTL = TIMER_CONTINUOUS_MODE | prescale_timer/* | TIMER_CTL_CNTDATEN_Msk*/;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     timer_base->CMP = cmp_timer;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     // Set vector
     NVIC_SetVector(TIMER_MODINIT.irq_n, (uint32_t) TIMER_MODINIT.var);
@@ -112,13 +112,13 @@ void lp_ticker_init(void)
     NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
 
     TIMER_EnableInt(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_EnableWakeup(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_Start(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     /* Wait for timer to start counting and raise active flag */
     while(! (timer_base->CTL & TIMER_CTL_ACTSTS_Msk));

targets/TARGET_NUVOTON/TARGET_M480/serial_api.c

@@ -25,6 +25,7 @@
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
 #include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -87,6 +88,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -1145,4 +1148,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_M480/sleep.c

@@ -22,6 +22,11 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
+
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
@@ -38,6 +43,12 @@ void hal_sleep(void)
  */
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();

targets/TARGET_NUVOTON/TARGET_NANO100/lp_ticker.c

@@ -19,9 +19,9 @@
 #if DEVICE_LPTICKER
 
 #include "sleep_api.h"
-#include "mbed_wait_api.h"
 #include "mbed_assert.h"
 #include "nu_modutil.h"
+#include "nu_timer.h"
 #include "nu_miscutil.h"
 
 /* Micro seconds per second */
@@ -102,13 +102,13 @@ void lp_ticker_init(void)
     MBED_ASSERT(cmp_timer >= TMR_CMP_MIN && cmp_timer <= TMR_CMP_MAX);
     // Continuous mode
     timer_base->CTL = TIMER_CONTINUOUS_MODE;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     timer_base->PRECNT = prescale_timer;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     timer_base->CMPR = cmp_timer;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     // Set vector
     NVIC_SetVector(TIMER_MODINIT.irq_n, (uint32_t) TIMER_MODINIT.var);
@@ -116,13 +116,13 @@ void lp_ticker_init(void)
     NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
 
     TIMER_EnableInt(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_EnableWakeup(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_Start(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     /* Wait for timer to start counting and raise active flag */
     while(! (timer_base->CTL & TIMER_CTL_TMR_ACT_Msk));

targets/TARGET_NUVOTON/TARGET_NANO100/serial_api.c

@@ -18,13 +18,14 @@
 
 #if DEVICE_SERIAL
 
-#include <string.h>
 #include "cmsis.h"
 #include "mbed_error.h"
 #include "mbed_assert.h"
 #include "PeripheralPins.h"
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
+#include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -76,6 +77,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -990,4 +993,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_NANO100/sleep.c

@@ -22,6 +22,11 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
+
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
@@ -38,6 +43,12 @@ void hal_sleep(void)
  */
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();

targets/TARGET_NUVOTON/TARGET_NUC472/lp_ticker.c

@@ -19,9 +19,9 @@
 #if DEVICE_LPTICKER
 
 #include "sleep_api.h"
-#include "mbed_wait_api.h"
 #include "mbed_assert.h"
 #include "nu_modutil.h"
+#include "nu_timer.h"
 #include "nu_miscutil.h"
 
 /* Micro seconds per second */
@@ -100,10 +100,10 @@ void lp_ticker_init(void)
     MBED_ASSERT(cmp_timer >= TMR_CMP_MIN && cmp_timer <= TMR_CMP_MAX);
     // Continuous mode
     timer_base->CTL = TIMER_CONTINUOUS_MODE | prescale_timer | TIMER_CTL_CNTDATEN_Msk;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     timer_base->CMP = cmp_timer;
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     // Set vector
     NVIC_SetVector(TIMER_MODINIT.irq_n, (uint32_t) TIMER_MODINIT.var);
@@ -111,13 +111,13 @@ void lp_ticker_init(void)
     NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
 
     TIMER_EnableInt(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_EnableWakeup(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     TIMER_Start(timer_base);
-    wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
+    nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
 
     /* Wait for timer to start counting and raise active flag */
     while(! (timer_base->CTL & TIMER_CTL_ACTSTS_Msk));

targets/TARGET_NUVOTON/TARGET_NUC472/serial_api.c

@@ -25,6 +25,7 @@
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
 #include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -87,6 +88,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -1136,4 +1139,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_NUC472/sleep.c

@@ -22,6 +22,11 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
+
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
@@ -38,6 +43,12 @@ void hal_sleep(void)
  */
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();

targets/TARGET_NUVOTON/nu_timer.c

@@ -0,0 +1,129 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2015-2016 Nuvoton
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "nu_timer.h"
+#include "mbed_power_mgmt.h"
+#include "mbed_critical.h"
+#include "us_ticker_api.h"
+#include "mbed_assert.h"
+
+void nu_countdown_init(struct nu_countdown_ctx_s *ctx, us_timestamp_t interval_us)
+{
+    core_util_critical_section_enter();
+    sleep_manager_lock_deep_sleep();
+    ctx->_ticker_data = get_us_ticker_data();
+    ctx->_interval_end_us = ticker_read_us(ctx->_ticker_data) + interval_us;
+    ctx->_expired = false;
+    core_util_critical_section_exit();
+}
+
+bool nu_countdown_expired(struct nu_countdown_ctx_s *ctx)
+{
+    core_util_critical_section_enter();
+    if (! ctx->_expired) {
+        ctx->_expired = ticker_read_us(ctx->_ticker_data) >= ctx->_interval_end_us;
+    }
+    core_util_critical_section_exit();
+    
+    return ctx->_expired;
+}
+
+void nu_countdown_free(struct nu_countdown_ctx_s *ctx)
+{
+    core_util_critical_section_enter();
+    sleep_manager_unlock_deep_sleep();
+    core_util_critical_section_exit();
+}
+
+
+void nu_busy_wait_us(uint32_t us)
+{
+    const uint32_t bits = us_ticker_get_info()->bits;
+    const uint32_t mask = (1 << bits) - 1;
+    MBED_ASSERT(us_ticker_get_info()->frequency == 1000000);
+    uint32_t prev = us_ticker_read();
+    while (1) {
+        const uint32_t cur = us_ticker_read();
+        const uint32_t elapsed = (cur - prev) & mask;
+        if (elapsed > us) {
+            break;
+        }
+        us -= elapsed;
+        prev = cur;
+    }
+}
+
+/* Delay 4 cycles per round by hand-counting instruction cycles
+ *
+ * The delay function here is implemented by just hand-counting instruction cycles rather than preferred
+ * H/W timer since it is to use in cases where H/W timer is not available. Usually, it can delay at least
+ * 4-cycles per round.
+ *
+ * In modern pipeline core, plus flash performance and other factors, we cannot rely accurately on hand-
+ * counting instruction cycles for expected delay cycles.
+ */
+#if defined(__CC_ARM)
+MBED_NOINLINE
+__asm void nu_delay_cycle_x4(uint32_t rounds)
+{
+// AStyle should not format inline assembly
+// *INDENT-OFF*
+1
+#if !defined(__CORTEX_M0)
+    NOP                         // 1 cycle
+#endif
+    SUBS a1, a1, #1             // 1 cycle
+    BCS  %BT1                   // 3 cycles(M0)/2 cycles(non-M0)
+    BX   lr
+// *INDENT-ON*
+}
+#elif defined (__ICCARM__)
+MBED_NOINLINE
+void nu_delay_cycle_x4(uint32_t rounds)
+{
+    __asm volatile(
+        "loop: \n"
+#if !defined(__CORTEX_M0)
+        " NOP \n"               // 1 cycle
+#endif
+        " SUBS %0, %0, #1 \n"   // 1 cycle
+        " BCS.n  loop\n"        // 3 cycles(M0)/2 cycles(non-M0)
+        : "+r"(rounds)
+        :
+        : "cc"
+    );
+}
+#elif  defined ( __GNUC__ ) ||  (defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050))
+MBED_NOINLINE
+void nu_delay_cycle_x4(uint32_t rounds)
+{
+    __asm__ volatile(
+        "%=:\n\t"
+#if !defined(__CORTEX_M0)
+        "NOP\n\t"               // 1 cycle
+#endif
+#if defined(__thumb__) && !defined(__thumb2__) && !defined(__ARMCC_VERSION)
+        "SUB  %0, #1\n\t"       // 1 cycle
+#else
+        "SUBS %0, %0, #1\n\t"   // 1 cycle
+#endif
+        "BCS  %=b\n\t"          // 3 cycles(M0)/2 cycles(non-M0)
+        : "+l"(rounds)
+        :
+        : "cc"
+    );
+}
+#endif

targets/TARGET_NUVOTON/nu_timer.h

@@ -20,8 +20,6 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include "cmsis.h"
-#include "mbed_power_mgmt.h"
-#include "mbed_critical.h"
 #include "ticker_api.h"
 #include "us_ticker_api.h"
 
@@ -58,33 +56,26 @@ struct nu_countdown_ctx_s {
     bool                    _expired;           // Expired or not
 };
 
-__STATIC_INLINE void nu_countdown_init(struct nu_countdown_ctx_s *ctx, us_timestamp_t interval_us)
-{
-    core_util_critical_section_enter();
-    sleep_manager_lock_deep_sleep();
-    ctx->_ticker_data = get_us_ticker_data();
-    ctx->_interval_end_us = ticker_read_us(ctx->_ticker_data) + interval_us;
-    ctx->_expired = false;
-    core_util_critical_section_exit();
-}
+void nu_countdown_init(struct nu_countdown_ctx_s *ctx, us_timestamp_t interval_us);
+bool nu_countdown_expired(struct nu_countdown_ctx_s *ctx);
+void nu_countdown_free(struct nu_countdown_ctx_s *ctx);
 
-__STATIC_INLINE bool nu_countdown_expired(struct nu_countdown_ctx_s *ctx)
-{
-    core_util_critical_section_enter();
-    if (! ctx->_expired) {
-        ctx->_expired = ticker_read_us(ctx->_ticker_data) >= ctx->_interval_end_us;
-    }
-    core_util_critical_section_exit();
-    
-    return ctx->_expired;
-}
 
-__STATIC_INLINE void nu_countdown_free(struct nu_countdown_ctx_s *ctx)
-{
-    core_util_critical_section_enter();
-    sleep_manager_unlock_deep_sleep();
-    core_util_critical_section_exit();
-}
+/* Replacement for wait_us when intermediary us ticker layer is disabled
+ *
+ * Use of wait_us directly from the low power ticker causes the system to deadlock during
+ * the sleep test because the sleep test disables the intermediary us ticker layer during
+ * the test.
+ *
+ * To prevent this lockup, nu_busy_wait_us is created to replace wait_us, which uses the us ticker
+ * directly rather than go though the intermediary us ticker layer.
+ *
+ * During wait period through nu_busy_wait_us, CPU would be busy spinning. 
+ */
+void nu_busy_wait_us(uint32_t us);
+
+/* Delay 4 cycles per round by hand-counting instruction cycles */
+void nu_delay_cycle_x4(uint32_t rounds);  
 
 #ifdef __cplusplus
 }