Preparing grounds for modem api

* Lays down ground for mbed modem_api
* Standardizes pin names relating to modem device for UBLOX C027 and MTS_DRAGONFLY_F411RE
  devices
* Ublox modem api is changed to use a standard, platform independent name so that same
  api could be used with multiple ubloc modems.
* DCD Polarity macro is added to assist the driver in knowing correct polarity

Author: Hasnain Virk

targets/TARGET_NXP/TARGET_LPC176X/TARGET_UBLOX_C027/C027_api.c

@@ -162,6 +162,11 @@ typedef enum {
     NC = (int)0xFFFFFFFF
 } PinName;
 
+#define ACTIVE_HIGH_POLARITY    1
+#define ACTIVE_LOW_POLARITY     0
+
+#define MDMDCD_POLARITY            ACTIVE_LOW_POLARITY
+
 typedef enum {
     PullUp = 0,
     PullDown = 3,

targets/TARGET_NXP/TARGET_LPC176X/TARGET_UBLOX_C027/C027_api.h

@@ -13,9 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-#include "C027_api.h"
+#include "ublox_low_level_api.h"
 
 // called before main
 void mbed_sdk_init() {
-	c027_init();
+	ublox_mdm_init();
 }

targets/TARGET_NXP/TARGET_LPC176X/TARGET_UBLOX_C027/PinNames.h

@@ -0,0 +1,97 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * 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 <stdbool.h>
+#include "hal/us_ticker_api.h"
+#include "platform/mbed_wait_api.h"
+#include "gpio_api.h"
+#include "ublox_low_level_api.h"
+
+static bool modemOn;
+static bool gpsOn;
+
+void ublox_mdm_init(void)
+{
+    gpio_t gpio;
+    // start with modem disabled 
+    gpio_init_out_ex(&gpio, MDMEN,     0);
+    gpio_init_out_ex(&gpio, MDMRST,    1);
+    gpio_init_out_ex(&gpio, MDMPWRON,  1);
+    gpio_init_out_ex(&gpio, MDMLVLOE,  1); // LVLEN:  1=disabled
+    gpio_init_out_ex(&gpio, MDMILVLOE, 0); // ILVLEN: 0=disabled
+    gpio_init_out_ex(&gpio, MDMUSBDET, 0);
+    gpio_init_out_ex(&gpio, MDMRTS,    0);
+    // start with gps disabled 
+    gpio_init_out_ex(&gpio, GPSEN,     0);
+    gpio_init_out_ex(&gpio, GPSRST,    1);
+    // led should be off
+    gpio_init_out_ex(&gpio, LED,       0);
+    
+    // Can't use wait_ms() as RTOS isn't initialised yet
+    //wait_ms(50); // when USB cable is inserted the interface chip issues
+    // Here's the code from the non-RTOS version
+    uint32_t start = us_ticker_read();
+    while ((us_ticker_read() - start) < 50000);
+}
+
+void ublox_mdm_powerOn(int usb)
+{
+    gpio_t gpio;
+    // turn on the mode by enabling power with power on pin low and correct USB detect level
+    gpio_init_out_ex(&gpio, MDMUSBDET,  usb ? 1 : 0);  // USBDET: 0=disabled, 1=enabled
+    if (!modemOn) { // enable modem
+        gpio_init_out_ex(&gpio, MDMEN, 1);        // LDOEN:  1=on
+        wait_ms(1);                   // wait until supply switched off
+        // now we can safely enable the level shifters
+        gpio_init_out_ex(&gpio, MDMLVLOE, 0);      // LVLEN:  0=enabled (uart/gpio)
+        if (gpsOn)
+            gpio_init_out_ex(&gpio, MDMILVLOE, 1); // ILVLEN: 1=enabled (i2c)
+    }
+}
+
+void ublox_mdm_powerOff(void)
+{
+    gpio_t gpio;
+    if (modemOn) {
+        // diable all level shifters
+        gpio_init_out_ex(&gpio, MDMILVLOE, 0);  // ILVLEN: 0=disabled (i2c)
+        gpio_init_out_ex(&gpio, MDMLVLOE, 1);   // LVLEN:  1=disabled (uart/gpio)
+        gpio_init_out_ex(&gpio,MDMUSBDET, 0);  // USBDET: 0=disabled
+        // now we can savely switch off the ldo
+        gpio_init_out_ex(&gpio, MDMEN, 0);      // LDOEN:  0=off
+        modemOn = false;
+    }
+}        
+
+void ublox_gps_powerOn(void)
+{
+    gpio_t gpio;
+    if (!gpsOn) {
+        // switch on power supply
+        gpio_init_out_ex(&gpio, GPSEN, 1);          // LDOEN: 1=on
+        wait_ms(1);                     // wait until supply switched off
+        if (modemOn)
+            gpio_init_out_ex(&gpio, MDMILVLOE, 1);  // ILVLEN: 1=enabled (i2c)
+    }
+}
+
+void ublox_gps_powerOff(void)
+{
+    gpio_t gpio;
+    if (gpsOn) {
+        gpio_init_out_ex(&gpio, MDMILVLOE, 0);   // ILVLEN: 0=disabled (i2c)
+        gpio_init_out_ex(&gpio, GPSEN, 0);       // LDOEN: 0=off
+    }
+}

targets/TARGET_NXP/TARGET_LPC176X/TARGET_UBLOX_C027/mbed_overrides.c

@@ -0,0 +1,37 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * 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.
+ */
+#ifndef UBLOX_LOW_LEVEL_H
+#define UBLOX_LOW_LEVEL_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void ublox_mdm_init(void);
+
+void ublox_mdm_powerOn(int usb);
+
+void ublox_mdm_powerOff(void);
+
+void ublox_gps_powerOn(void);
+
+void ublox_gps_powerOff(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // UBLOX_LOW_LEVEL_H

targets/TARGET_NXP/TARGET_LPC176X/TARGET_UBLOX_C027/ublox_low_level_api.c

@@ -38,6 +38,9 @@ extern "C" {
 #endif
 
 typedef enum {
+    // Not connected
+    NC = -1,
+
     PA_0  = 0x00,
     PA_1  = 0x01,
     PA_2  = 0x02,
@@ -141,10 +144,20 @@ typedef enum {
     RADIO_RX    = PC_6,
     RADIO_RTS   = PB_10,
     RADIO_CTS   = PB_12,
-    RADIO_DCD   = D5,
-    RADIO_DSR   = D8,
-    RADIO_DTR   = D4,
-    RADIO_RI    = D9,
+    RADIO_DCD   = NC,
+    RADIO_DSR   = NC,
+    RADIO_DTR   = NC,
+    RADIO_RI    = NC,
+    MDMPWRON  = PC_13, // 3G_ONOFF DragonFly Design Guide, Page No. 16
+    MDMTXD = RADIO_TX, // Transmit Data
+    MDMRXD = RADIO_RX, // Receive Data
+    MDMRTS = RADIO_RTS, // Request to Send
+    MDMCTS = RADIO_CTS, // Clear to Send
+    MDMDCD = RADIO_DCD, // Data Carrier Detect
+    MDMDSR = RADIO_DSR, // Data Set Ready
+    MDMDTR = RADIO_DTR, // Data Terminal Ready
+    MDMRI  = RADIO_RI, // Ring Indicator
+
     WAKEUP      = D3,
 
     // I2C1 and I2C3 are available on Arduino pins
@@ -175,12 +188,16 @@ typedef enum {
     SPI_MISO    = SPI3_MISO,
     SPI_SCK     = SPI3_SCK,
     SPI_CS1     = PA_4,
-    SPI_CS2     = PB_14,
+    SPI_CS2     = PB_14
 
-    // Not connected
-    NC = (int)0xFFFFFFFF
 } PinName;
 
+#define ACTIVE_HIGH_POLARITY    1
+#define ACTIVE_LOW_POLARITY     0
+
+#define MDMDCD_POLARITY            ACTIVE_HIGH_POLARITY
+
+
 #ifdef __cplusplus
 }
 #endif

targets/TARGET_NXP/TARGET_LPC176X/TARGET_UBLOX_C027/ublox_low_level_api.h

@@ -248,7 +248,7 @@
         "supported_form_factors": ["ARDUINO"],
         "core": "Cortex-M3",
         "supported_toolchains": ["ARM", "uARM", "GCC_ARM", "GCC_CR", "IAR"],
-        "extra_labels": ["NXP", "LPC176X", "FLASH_CMSIS_ALGO"],
+        "extra_labels": ["NXP", "LPC176X", "FLASH_CMSIS_ALGO", "UBLOX_MODEM"],
         "macros": ["TARGET_LPC1768"],
         "inherits": ["LPCTarget"],
         "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "DEBUG_AWARENESS", "ERROR_RED", "ETHERNET", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES", "FLASH"],