microbit-dal: Minimalist Keyboard HID Service

inc/bluetooth/MicroBitDeviceInformationService.h

@@ -0,0 +1,145 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 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 __BLE_HID_DEVICE_INFORMATION_SERVICE_H__
+#define __BLE_HID_DEVICE_INFORMATION_SERVICE_H__
+
+#include "ble/BLE.h"
+
+typedef struct
+{
+    uint8_t vendorID_source;
+    uint16_t vendorID;
+    uint16_t productID;
+    uint16_t productVersion;
+} PnPID_t;
+
+/**
+* @class HIDDeviceInformationService
+* @brief BLE Device Information Service <br>
+* Service: https://developer.bluetooth.org/gatt/services/Pages/ServiceViewer.aspx?u=org.bluetooth.service.device_information.xml <br>
+* Manufacturer Name String Char: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.manufacturer_name_string.xml
+*/
+class HIDDeviceInformationService {
+public:
+    /**
+     * @brief Device Information Service Constructor.
+     *
+     * @param[ref] _ble
+     *                BLE object for the underlying controller.
+     * @param[in] manufacturersName
+     *                This characteristic represents the name of the
+     *                manufacturer of the device. The name is copied into the
+     *                BLE stack during this constructor.
+     * @param[in] modelNumber
+     *                This characteristic represents the model number that is
+     *                assigned by the device vendor. The value is copied into
+     *                the BLE stack during this constructor.
+     * @param[in] serialNumber
+     *                This characteristic represents the serial number for a
+     *                particular instance of the device.  The value is copied
+     *                into the BLE stack during this constructor.
+     * @param[in] hardwareRevision
+     *                This characteristic represents the hardware revision for
+     *                the hardware within the device. The value is copied
+     *                into the BLE stack during this constructor.
+     * @param[in] firmwareRevision
+     *                This characteristic represents the firmware revision for
+     *                the firmware within the device. The value is copied
+     *                into the BLE stack during this constructor.
+     * @param[in] softwareRevision
+     *                This characteristic represents the software revision for
+     *                the software within the device. The value is copied
+     *                into the BLE stack during this constructor.
+     * @param[in] pnpID
+     *                This characteristic represents HID-specific information,
+     *                such as vendor id, product id and version.
+     */
+    HIDDeviceInformationService(BLE            &_ble,
+                             const char     *manufacturersName = NULL,
+                             const char     *modelNumber       = NULL,
+                             const char     *serialNumber      = NULL,
+                             const char     *hardwareRevision  = NULL,
+                             const char     *firmwareRevision  = NULL,
+                             const char     *softwareRevision  = NULL,
+                             PnPID_t        *PnPID             = NULL) :
+        ble(_ble)
+    {
+        static bool serviceAdded = false; /* We should only ever need to add the information service once. */
+        if (serviceAdded) {
+            return;
+        }
+
+        GattCharacteristic manufacturersNameStringCharacteristic(GattCharacteristic::UUID_MANUFACTURER_NAME_STRING_CHAR,
+                                              (uint8_t *)manufacturersName,
+                                              (manufacturersName != NULL) ? strlen(manufacturersName) : 0, /* minLength */
+                                              (manufacturersName != NULL) ? strlen(manufacturersName) : 0, /* maxLength */
+                                              GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ);
+
+        GattCharacteristic modelNumberStringCharacteristic(GattCharacteristic::UUID_MODEL_NUMBER_STRING_CHAR,
+                                        (uint8_t *)modelNumber,
+                                        (modelNumber != NULL) ? strlen(modelNumber) : 0, /* minLength */
+                                        (modelNumber != NULL) ? strlen(modelNumber) : 0, /* maxLength */
+                                        GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ);
+
+        GattCharacteristic serialNumberStringCharacteristic(GattCharacteristic::UUID_SERIAL_NUMBER_STRING_CHAR,
+                                         (uint8_t *)serialNumber,
+                                         (serialNumber != NULL) ? strlen(serialNumber) : 0, /* minLength */
+                                         (serialNumber != NULL) ? strlen(serialNumber) : 0, /* maxLength */
+                                         GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ);
+
+        GattCharacteristic hardwareRevisionStringCharacteristic(GattCharacteristic::UUID_HARDWARE_REVISION_STRING_CHAR,
+                                             (uint8_t *)hardwareRevision,
+                                             (hardwareRevision != NULL) ? strlen(hardwareRevision) : 0, /* minLength */
+                                             (hardwareRevision != NULL) ? strlen(hardwareRevision) : 0, /* maxLength */
+                                             GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ);
+
+        GattCharacteristic firmwareRevisionStringCharacteristic(GattCharacteristic::UUID_FIRMWARE_REVISION_STRING_CHAR,
+                                             (uint8_t *)firmwareRevision,
+                                             (firmwareRevision != NULL) ? strlen(firmwareRevision) : 0, /* minLength */
+                                             (firmwareRevision != NULL) ? strlen(firmwareRevision) : 0, /* maxLength */
+                                             GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ);
+
+        GattCharacteristic softwareRevisionStringCharacteristic(GattCharacteristic::UUID_SOFTWARE_REVISION_STRING_CHAR,
+                                             (uint8_t *)softwareRevision,
+                                             (softwareRevision != NULL) ? strlen(softwareRevision) : 0, /* minLength */
+                                             (softwareRevision != NULL) ? strlen(softwareRevision) : 0, /* maxLength */
+                                             GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ);
+
+        GattCharacteristic pnpIDCharacteristic(GattCharacteristic::UUID_PNP_ID_CHAR, (uint8_t *)PnPID, 7,7,GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ);
+
+        GattCharacteristic *charTable[] = {&manufacturersNameStringCharacteristic,
+                                           &modelNumberStringCharacteristic,
+                                           &serialNumberStringCharacteristic,
+                                           &hardwareRevisionStringCharacteristic,
+                                           &firmwareRevisionStringCharacteristic,
+                                           &softwareRevisionStringCharacteristic,
+                                           &pnpIDCharacteristic};
+
+        GattService         deviceInformationService(GattService::UUID_DEVICE_INFORMATION_SERVICE, charTable,
+                                                     sizeof(charTable) / sizeof(GattCharacteristic *));
+
+        // for some reason, this causes the micro:bit build to break.
+        // pnpIDCharacteristic.requireSecurity(SecurityManager::SECURITY_MODE_ENCRYPTION_NO_MITM);
+        ble.addService(deviceInformationService);
+        serviceAdded = true;
+    }
+
+protected:
+    BLE                 &ble;
+};
+
+#endif /* #ifndef __BLE_HID_DEVICE_INFORMATION_SERVICE_H__*/

inc/bluetooth/MicroBitKeyboardService.h

@@ -0,0 +1,123 @@
+#ifndef MICROBIT_KEYBOARD_SERVICE_H
+#define MICROBIT_KEYBOARD_SERVICE_H
+
+#include "hid/BluetoothHIDTypes.h"
+#include "hid/BluetoothHIDKeys.h"
+#include "ble/services/BatteryService.h"
+#include "ManagedString.h"
+#include "ble/BLE.h"
+#include "ScanParametersService.h"
+
+#include "MicroBitComponent.h"
+
+#define MICROBIT_HID_ADVERTISING_INT    100
+#define MICROBIT_HID_STATE_IN_USE       0x02
+
+/**
+  * This class represents a Bluetooth HID device, specifically, a keyboard instance.
+  *
+  * A few things to note:
+  *     - HID devices require a battery service (automatically instantiated with this class)
+  *     - Security is required, this class has only been tested using Just Works pairing.
+  *     - On mac to get it to pair, you may have to interrogate a secure characteristic of the micro:bit via LightBlue
+  *       in order to initiate pairing.
+  *     - It is designed to be as light weight as possible, and employs tactics like the stack allocation of
+  *       gatt characteristics to alleviate RAM pressures.
+  */
+class MicroBitKeyboardService : public MicroBitComponent
+{
+    private:
+    BLEDevice& ble;
+    BatteryService* batteryService;
+    ScanParametersService* paramsService;
+
+    uint16_t inputDescriptorHandle;
+    uint16_t outputDescriptorHandle;
+    uint16_t featureDescriptorHandle;
+    uint16_t pmCharacteristicHandle;
+    uint16_t kInCharacteristicHandle;
+    uint16_t kOutCharacteristicHandle;
+    uint16_t rMapCharacteristicHandle;
+    uint16_t infoCharacteristicHandle;
+    uint16_t cpCharacteristicHandle;
+
+    GattAttribute* inputDescriptor;
+    GattAttribute* outputDescriptor;
+    GattAttribute* featureDescriptor;
+    GattAttribute* reportMapExternalRef;
+
+    GattCharacteristic* protocolModeCharacteristic;
+    GattCharacteristic* controlPointCharacteristic;
+    GattCharacteristic* keyboardInCharacteristic;
+    GattCharacteristic* bootInCharacteristic;
+
+    /**
+      * A simple helper function that "returns" our most recently "pressed" key to
+      * the up position.
+      */
+    void keyUp();
+
+    /**
+      * Places and translates a single ascii character into a keyboard
+      * value, placing it in our input buffer.
+      */
+    int putc(const char c);
+
+    public:
+
+    /**
+      * Constructor for our keyboard service.
+      *
+      * Creates a collection of characteristics, instantiates a battery service,
+      * and modifies advertisement data.
+      */
+    MicroBitKeyboardService(BLEDevice& _ble, bool pairing);
+
+    /**
+      * Send a "Special" non-ascii keyboard key, defined in BluetoothHIDKeys.h
+      */
+    int send(MediaKey key);
+
+    /**
+      * Send a single character to our host.
+      *
+      * @param c the character to send
+      *
+      * @return MICROBIT_NOT_SUPPORTED if the micro:bit is not connected to a host.
+      */
+    int send(const char c);
+
+    /**
+      * Send a buffer of characters to our host.
+      *
+      * @param data the characters to send
+      *
+      * @param len the number of characters in the buffer.
+      *
+      * @return MICROBIT_NOT_SUPPORTED if the micro:bit is not connected to a host.
+      */
+    int send(const char* data, int len);
+
+    /**
+      * Send a ManagedString to our host.
+      *
+      * @param data the string to send
+      *
+      * @return MICROBIT_NOT_SUPPORTED if the micro:bit is not connected to a host.
+      */
+    int send(ManagedString data);
+
+    void debugRead(const GattReadCallbackParams *params);
+
+    void debugWrite(const GattWriteCallbackParams *params);
+
+    /**
+      * Destructor.
+      *
+      * Frees our heap allocated characteristic and service, and remove this instance
+      * from our system timer interrupt.
+      */
+    ~MicroBitKeyboardService();
+};
+
+#endif

inc/bluetooth/ScanParametersService.h

@@ -0,0 +1,58 @@
+#ifndef __BLE_SCAN_PARAMETERS_SERVICE_H__
+#define __BLE_SCAN_PARAMETERS_SERVICE_H__
+
+#include "ble/BLE.h"
+
+#pragma pack(push, 1)
+typedef struct {
+	uint16_t LE_Scan_Interval;
+	uint16_t LE_Scan_Window;
+} ScanIntervalWindow_t;
+#pragma pack(pop)
+
+class ScanParametersService {
+public:
+	ScanParametersService(
+		BLE &_ble
+	) :
+		ble(_ble),
+		scanIntervalWindowCharacteristic(
+			GattCharacteristic::UUID_SCAN_INTERVAL_WINDOW_CHAR,
+			(uint8_t*)&scanIntervalWindowData,
+			sizeof(scanIntervalWindowData),
+			sizeof(scanIntervalWindowData),
+			GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE_WITHOUT_RESPONSE
+		),
+		scanRefreshCharacteristic(
+			GattCharacteristic::UUID_SCAN_REFRESH_CHAR,
+			&scanRefreshData,
+			sizeof(scanIntervalWindowData),
+			sizeof(scanIntervalWindowData),
+			GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY
+		)
+	{
+		GattCharacteristic *charTable[] = {
+			&scanIntervalWindowCharacteristic,
+			&scanRefreshCharacteristic
+		};
+
+		GattService scanParametersService(
+			GattService::UUID_SCAN_PARAMETERS_SERVICE,
+			charTable,
+			sizeof(charTable) / sizeof(GattCharacteristic *)
+		);
+
+		ble.addService(scanParametersService);
+	}
+
+protected:
+	BLE& ble;
+
+	ScanIntervalWindow_t scanIntervalWindowData;
+	uint8_t scanRefreshData;
+
+	GattCharacteristic scanIntervalWindowCharacteristic;
+	GattCharacteristic scanRefreshCharacteristic;
+};
+
+#endif