Update Dragonfly Nano(MTQN) power on/off so soft_power_on() performs a reset

targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L471xG/TARGET_MTS_DRAGONFLY_L471QG/ONBOARD_SARA4_PPP.cpp

@@ -29,6 +29,7 @@ using namespace mbed;
 
 ONBOARD_SARA4_PPP::ONBOARD_SARA4_PPP(FileHandle *fh) : SARA4_PPP(fh)
 {
+    initialized = 0;
 }
 
 nsapi_error_t ONBOARD_SARA4_PPP::hard_power_on()
@@ -45,6 +46,8 @@ nsapi_error_t ONBOARD_SARA4_PPP::hard_power_off()
 
 nsapi_error_t ONBOARD_SARA4_PPP::soft_power_on()
 {
+    // See base function description. This function is for power on but reset too.
+    onboard_modem_power_down();
     onboard_modem_power_up();
     return NSAPI_ERROR_OK;
 }
@@ -80,55 +83,105 @@ void ONBOARD_SARA4_PPP::onboard_modem_init()
 {
     gpio_t gpio;
 
-    // Take us out of reset
+    // Enable radio power regulator and buffer, configure RESET_N and PWR_ON.
     gpio_init_inout(&gpio, RADIO_PWR, PIN_OUTPUT, PushPullNoPull,   1);
     gpio_init_inout(&gpio, BUF_EN, PIN_OUTPUT, OpenDrainNoPull,   0);
     gpio_init_out_ex(&gpio, MDMRST, 0);
     gpio_init_out_ex(&gpio, MDMPWRON, 0);
     gpio_init_inout(&gpio, RADIO_DTR, PIN_OUTPUT, OpenDrainNoPull, 0);
+    initialized = 1;
 }
 
 void ONBOARD_SARA4_PPP::onboard_modem_deinit()
 {
+    // Make sure to power down before removing power!
     onboard_modem_power_down();
     gpio_t gpio;
 
-    // Back into reset
+    // Set all to input no pull. Let pull resistors do their thing. Allows for lowest power draw.
-    gpio_init_out_ex(&gpio, MDMRST, 1);
+    // Disable radio power regulator and buffer.
-    gpio_init_out_ex(&gpio, MDMPWRON, 1);
+    gpio_init_inout(&gpio, MDMRST, PIN_INPUT, PullNone, 1);
-    gpio_init_inout(&gpio, BUF_EN, PIN_OUTPUT, OpenDrainNoPull,   1);
+    gpio_init_inout(&gpio, MDMPWRON, PIN_INPUT, PullNone, 1);
-    gpio_init_inout(&gpio, RADIO_PWR, PIN_OUTPUT, PushPullNoPull,   0);
+    gpio_init_inout(&gpio, BUF_EN, PIN_INPUT, PullNone, 1);
-    gpio_init_inout(&gpio, RADIO_DTR, PIN_OUTPUT, OpenDrainNoPull, 1);
+    gpio_init_inout(&gpio, RADIO_PWR, PIN_INPUT, PullNone, 0);
+    gpio_init_inout(&gpio, RADIO_DTR, PIN_INPUT, PullNone, 1);
+    initialized = 0;
 }
 
 void ONBOARD_SARA4_PPP::onboard_modem_power_up()
 {
+    // Make sure the radio is initialized so it can be powered on.
+    if (!initialized){
         onboard_modem_init();
-
-    gpio_t gpio;
-    gpio_init_in(&gpio, MON_1V8);
-
-    if(gpio_is_connected(&gpio) && !gpio_read(&gpio)) {
-        unsigned int i = 0;
-        while(i < 3)
-        {
-            press_power_button(150000);
-            thread_sleep_for(250);
-
-            if(gpio_read(&gpio))
-            {
-                break;
     }
-            i++;
+
+    gpio_t radioOn;
+    gpio_init_in(&radioOn, MON_1V8);
+
+    // Need volatile so 1.8v check is not optimized out.
+    volatile int v1_8 = gpio_read(&radioOn);
+
+    // If radio is on, do nothing.
+    if (v1_8) {
+        return;
     }
+
+    uint8_t retries = 5;
+    do {
+        // If it hasn't turned on after multiple tries, exit and return.
+        if(0 == retries--) {
+            return;
         }
+        // Activate PWR_ON for 150ms-3.2s to switch on. Reference ublox SARA-R4 data sheet.
+        press_power_button(160000);
+        v1_8 = gpio_read(&radioOn);
+    } while (!v1_8);
+    // Takes ~4.5s to power on. Reference SARA-R4 system integration manual... module power-on.
+    // Pad a few more seconds to be sure.
+    thread_sleep_for(8000);
 }
 
 void ONBOARD_SARA4_PPP::onboard_modem_power_down()
 {
-    /* Activate PWR_ON for 1.5s to switch off */
+    gpio_t radioOn;
-    press_power_button(1500000);
+    gpio_init_in(&radioOn, MON_1V8);
-    // check for 1.8v low if not, take reset low for 10s
+    // Need volatile so 1.8v check is not optimized out.
+    volatile int v1_8 = gpio_read(&radioOn);
+    // Do nothing if it's already off.
+    if (!v1_8) {
+        return;
+    }
+
+    // Make sure the I/O are properly initialized.
+    if (!initialized){
+        onboard_modem_init();
+    }
+    // Activate PWR_ON for at least 1.5s to switch off. Reference ublox SARA-R4 data sheet.
+    press_power_button(1600000);
+
+    // wait a max of 40s for 1.8v to go low. Reference AT command guide +CPWROFF estimated response.
+    uint8_t timeout = 40;
+    do {
+        thread_sleep_for(1000);
+        v1_8 = gpio_read(&radioOn);
+    } while (v1_8 && timeout--);
+
+    // hold RESET_N low (inverted) at least 10s to power down the radio.
+    if (v1_8) {
+        gpio_t gpio;
+        gpio_init_out_ex(&gpio, RADIO_RESET, 1);
+        thread_sleep_for(11000);
+        gpio_write(&gpio, 0);
+    }
+
+    v1_8 = gpio_read(&radioOn);
+    // Cut power to the radio if it's still not powered off.
+    if (v1_8) {
+        gpio_t gpio;
+        gpio_init_inout(&gpio, RADIO_PWR, PIN_INPUT, PullNone, 0);
+        thread_sleep_for(1000);
+        initialized = 0;
+    }
 }
 
 #endif // MBED_CONF_NSAPI_PRESENT

targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L471xG/TARGET_MTS_DRAGONFLY_L471QG/ONBOARD_SARA4_PPP.h

@@ -32,6 +32,8 @@ public:
     virtual nsapi_error_t soft_power_off();
 
 private:
+    uint8_t initialized;
+
     void press_power_button(int time_ms);
 
     void onboard_modem_init();