Cellular: Fix BG96 power on and connect

Author: Ari Parkkila

UNITTESTS/features/cellular/framework/AT/at_cellulardevice/unittest.cmake

@@ -43,6 +43,7 @@ set(unittest-test-sources
   stubs/SerialBase_stub.cpp
   stubs/CellularStateMachine_stub.cpp
   stubs/CellularContext_stub.cpp
+  stubs/ThisThread_stub.cpp
   stubs/ConditionVariable_stub.cpp
   stubs/Mutex_stub.cpp
 )

features/cellular/framework/AT/ATHandler.cpp

@@ -926,7 +926,7 @@ void ATHandler::set_3gpp_error(int err, DeviceErrorType error_type)
         for (size_t i = 0; i < sizeof(map_3gpp_errors) / sizeof(map_3gpp_errors[0]); i++) {
             if (map_3gpp_errors[i][0] == err) {
                 _last_3gpp_error = map_3gpp_errors[i][1];
-                tr_debug("AT3GPP error code %d", get_3gpp_error());
+                tr_error("AT3GPP error code %d", get_3gpp_error());
                 break;
             }
         }
@@ -943,7 +943,7 @@ void ATHandler::at_error(bool error_code_expected, DeviceErrorType error_type)
             set_3gpp_error(err, error_type);
             _last_at_err.errCode = err;
             _last_at_err.errType = error_type;
-            tr_error("AT error code %ld", err);
+            tr_warn("AT error code %ld", err);
         } else {
             tr_warn("ATHandler ERROR reading failed");
         }

features/cellular/framework/AT/AT_CellularContext.cpp

@@ -608,6 +608,7 @@ nsapi_error_t AT_CellularContext::open_data_channel()
                   connected, or timeout after 30 seconds*/
     nsapi_error_t err = nsapi_ppp_connect(_at.get_file_handle(), callback(this, &AT_CellularContext::ppp_status_cb), _uname, _pwd, (nsapi_ip_stack_t)_pdp_type);
     if (err) {
+        tr_error("nsapi_ppp_connect failed");
         ppp_disconnected();
     }
 
@@ -993,6 +994,7 @@ void AT_CellularContext::cellular_callback(nsapi_event_t ev, intptr_t ptr)
                 tr_info("cellular_callback: PPP mode and NSAPI_STATUS_DISCONNECTED");
                 _cb_data.error = NSAPI_ERROR_NO_CONNECTION;
                 _is_connected = false;
+                ppp_disconnected();
             }
         }
 #else

features/cellular/framework/AT/AT_CellularDevice.cpp

@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 
+#include "rtos/ThisThread.h"
 #include "CellularUtil.h"
 #include "AT_CellularDevice.h"
 #include "AT_CellularInformation.h"
@@ -202,6 +203,7 @@ nsapi_error_t AT_CellularDevice::get_sim_state(SimState &state)
     _at->flush();
     nsapi_error_t error = _at->at_cmd_str("+CPIN", "?", simstr, sizeof(simstr));
     ssize_t len = strlen(simstr);
+    device_err_t err = _at->get_last_device_error();
     _at->unlock();
 
     if (len != -1) {
@@ -213,7 +215,6 @@ nsapi_error_t AT_CellularDevice::get_sim_state(SimState &state)
             state = SimStatePukNeeded;
         } else {
             simstr[len] = '\0';
-            tr_error("Unknown SIM state %s", simstr);
             state = SimStateUnknown;
         }
     } else {
@@ -229,7 +230,11 @@ nsapi_error_t AT_CellularDevice::get_sim_state(SimState &state)
             tr_error("SIM PUK required");
             break;
         case SimStateUnknown:
-            tr_warn("SIM state unknown");
+            if (err.errType == DeviceErrorTypeErrorCME && err.errCode == 14) {
+                tr_info("SIM busy");
+            } else {
+                tr_warn("SIM state unknown");
+            }
             break;
         default:
             tr_info("SIM is ready");
@@ -443,12 +448,18 @@ nsapi_error_t AT_CellularDevice::init()
     setup_at_handler();
 
     _at->lock();
-    _at->flush();
-    _at->at_cmd_discard("E0", "");
-
-    _at->at_cmd_discard("+CMEE", "=1");
-
-    _at->at_cmd_discard("+CFUN", "=1");
+    for (int retry = 1; retry <= 3; retry++) {
+        _at->clear_error();
+        _at->flush();
+        _at->at_cmd_discard("E0", "");
+        _at->at_cmd_discard("+CMEE", "=1");
+        _at->at_cmd_discard("+CFUN", "=1");
+        if (_at->get_last_error() == NSAPI_ERROR_OK) {
+            break;
+        }
+        tr_debug("Wait 100ms to init modem");
+        rtos::ThisThread::sleep_for(100); // let modem have time to get ready
+    }
 
     return _at->unlock_return_error();
 }

features/cellular/framework/AT/AT_CellularNetwork.cpp

@@ -211,8 +211,9 @@ nsapi_error_t AT_CellularNetwork::set_registration(const char *plmn)
     if (!plmn) {
         tr_debug("Automatic network registration");
         NWRegisteringMode mode;
-        get_network_registering_mode(mode);
-
+        if (get_network_registering_mode(mode) != NSAPI_ERROR_OK) {
+            return NSAPI_ERROR_DEVICE_ERROR;
+        }
         if (mode != NWModeAutomatic) {
             return _at.at_cmd_discard("+COPS", "=0");
         }

features/cellular/framework/device/CellularDevice.cpp

@@ -234,6 +234,9 @@ nsapi_error_t CellularDevice::shutdown()
     }
     CellularContext *curr = get_context_list();
     while (curr) {
+        if (curr->is_connected()) {
+            curr->disconnect();
+        }
         curr->cellular_callback(NSAPI_EVENT_CONNECTION_STATUS_CHANGE, NSAPI_STATUS_DISCONNECTED);
         curr = (CellularContext *)curr->_next;
     }

features/cellular/framework/device/CellularStateMachine.cpp

@@ -367,6 +367,7 @@ void CellularStateMachine::state_device_ready()
             }
         } else {
             _status = 0;
+            _is_retry = true;
             enter_to_state(STATE_INIT);
         }
     }

features/cellular/framework/targets/QUECTEL/BG96/QUECTEL_BG96.cpp

@@ -97,92 +97,35 @@ void QUECTEL_BG96::set_ready_cb(Callback<void()> callback)
     _at->set_urc_handler(DEVICE_READY_URC, callback);
 }
 
-nsapi_error_t QUECTEL_BG96::hard_power_on()
-{
-    if (_pwr.is_connected()) {
-        tr_info("Modem power on");
-        ThisThread::sleep_for(250);
-        _pwr = !_active_high;
-        ThisThread::sleep_for(250); // BG96_Hardware_Design_V1.1 says 100 ms, but 250 ms seems to be more robust
-        _pwr = _active_high;
-        ThisThread::sleep_for(500);
-    }
-
-    return NSAPI_ERROR_OK;
-}
-
 nsapi_error_t QUECTEL_BG96::soft_power_on()
-{
-    if (!_rst.is_connected()) {
-        return NSAPI_ERROR_OK;
-    }
-
-    tr_info("Reset modem");
-    _rst = !_active_high;
-    ThisThread::sleep_for(100);
-    _rst = _active_high;
-    ThisThread::sleep_for(150 + 460); // RESET_N timeout from BG96_Hardware_Design_V1.1
-    _rst = !_active_high;
-    ThisThread::sleep_for(500);
-
-    // wait for RDY
-    _at->lock();
-    _at->set_at_timeout(10 * 1000);
-    _at->resp_start();
-    _at->set_stop_tag("RDY");
-    bool rdy = _at->consume_to_stop_tag();
-    _at->set_stop_tag(OK);
-    _at->restore_at_timeout();
-
-    if (!rdy) {
-        // check if modem was silently powered on
-        _at->clear_error();
-        _at->set_at_timeout(100);
-        _at->at_cmd_discard("", ""); //Send AT
-        _at->restore_at_timeout();
-    }
-    return _at->unlock_return_error();
-}
-
-nsapi_error_t QUECTEL_BG96::hard_power_off()
 {
     if (_pwr.is_connected()) {
-        tr_info("Modem power off");
-        _pwr = _active_high;
-        ThisThread::sleep_for(650); // from BG96_Hardware_Design_V1.1
-        _pwr = !_active_high;
+        tr_info("QUECTEL_BG96::soft_power_on");
+        // check if modem was powered on already
+        if (wake_up()) {
+            return NSAPI_ERROR_OK;
+        }
+        if (!wake_up(true)) {
+            tr_error("Modem not responding");
+            soft_power_off();
+            return NSAPI_ERROR_DEVICE_ERROR;
+        }
     }
 
     return NSAPI_ERROR_OK;
 }
 
-nsapi_error_t QUECTEL_BG96::init()
+nsapi_error_t QUECTEL_BG96::soft_power_off()
 {
-    setup_at_handler();
-
-    int retry = 0;
-
     _at->lock();
-    _at->flush();
-    _at->at_cmd_discard("E0", ""); // echo off
-
-    _at->at_cmd_discard("+CMEE", "=1"); // verbose responses
-
+    _at->cmd_start("AT+QPOWD");
+    _at->cmd_stop_read_resp();
     if (_at->get_last_error() != NSAPI_ERROR_OK) {
-        return _at->unlock_return_error();
-    }
-
-    do {
-        _at->clear_error();
-        _at->at_cmd_discard("+CFUN", "=1"); // set full functionality
-        if (_at->get_last_error() == NSAPI_ERROR_OK) {
-            break;
+        tr_warn("Force modem off");
+        if (_pwr.is_connected()) {
+            press_button(_pwr, 650); // BG96_Hardware_Design_V1.1: Power off signal at least 650 ms
         }
-        // wait some time that modem gets ready for CFUN command, and try again
-        retry++;
-        ThisThread::sleep_for(64); // experimental value
-    } while (retry < 3);
-
+    }
     return _at->unlock_return_error();
 }
 
@@ -215,3 +158,52 @@ void QUECTEL_BG96::urc_pdpdeact()
     }
     send_disconnect_to_context(cid);
 }
+
+void QUECTEL_BG96::press_button(DigitalOut &button, uint32_t timeout)
+{
+    if (!button.is_connected()) {
+        return;
+    }
+    button = _active_high;
+    ThisThread::sleep_for(timeout);
+    button = !_active_high;
+}
+
+bool QUECTEL_BG96::wake_up(bool reset)
+{
+    // check if modem is already ready
+    _at->lock();
+    _at->flush();
+    _at->set_at_timeout(30);
+    _at->cmd_start("AT");
+    _at->cmd_stop_read_resp();
+    nsapi_error_t err = _at->get_last_error();
+    _at->restore_at_timeout();
+    _at->unlock();
+    // modem is not responding, power it on
+    if (err != NSAPI_ERROR_OK) {
+        if (!reset) {
+            // BG96_Hardware_Design_V1.1 requires VBAT to be stable over 30 ms, that's handled above
+            tr_info("Power on modem");
+            press_button(_pwr, 250); // BG96_Hardware_Design_V1.1 requires time 100 ms, but 250 ms seems to be more robust
+        } else {
+            tr_warn("Reset modem");
+            press_button(_rst, 150); // BG96_Hardware_Design_V1.1 requires RESET_N timeout at least 150 ms
+        }
+        _at->lock();
+        // According to BG96_Hardware_Design_V1.1 USB is active after 4.2s, but it seems to take over 5s
+        _at->set_at_timeout(6000);
+        _at->resp_start();
+        _at->set_stop_tag("RDY");
+        bool rdy = _at->consume_to_stop_tag();
+        _at->set_stop_tag(OK);
+        _at->restore_at_timeout();
+        _at->unlock();
+        if (!rdy) {
+            return false;
+        }
+    }
+
+    // sync to check that AT is really responsive and to clear garbage
+    return _at->sync(500);
+}

features/cellular/framework/targets/QUECTEL/BG96/QUECTEL_BG96.h

@@ -41,17 +41,16 @@ class QUECTEL_BG96 : public AT_CellularDevice {
     virtual AT_CellularContext *create_context_impl(ATHandler &at, const char *apn, bool cp_req = false, bool nonip_req = false);
     virtual AT_CellularInformation *open_information_impl(ATHandler &at);
     virtual void set_ready_cb(Callback<void()> callback);
-    virtual nsapi_error_t hard_power_on();
-    virtual nsapi_error_t hard_power_off();
     virtual nsapi_error_t soft_power_on();
-    virtual nsapi_error_t init();
+    virtual nsapi_error_t soft_power_off();
     virtual void set_at_urcs_impl();
 
 public:
     void handle_urc(FileHandle *fh);
 
 private:
-    nsapi_error_t press_power_button(uint32_t timeout);
+    void press_button(DigitalOut &button, uint32_t timeout);
+    bool wake_up(bool reset = false);
     bool _active_high;
     DigitalOut _pwr;
     DigitalOut _rst;