Lancaster University / BLE_API

Lancaster University's fork of the mbed BLE API. Lives on github, https://github.com/lancaster-university/BLE_API

Dependents:   microbit-dal microbit-dal microbit-ble-open microbit-dal ... more

Fork of BLE_API by Bluetooth Low Energy

ble/services/UARTService.h@712:b04b5db36865, 2015-06-19 (annotated)

Committer:
rgrover1
Date:
Fri Jun 19 15:53:29 2015 +0100
Revision:
712:b04b5db36865
Child:
717:3129b149a6b2
Synchronized with git rev 75beb803

Author: Rohit Grover

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UserRevisionLine numberNew contents of line
rgrover1 712:b04b5db36865 1 /* mbed Microcontroller Library
rgrover1 712:b04b5db36865 2 * Copyright (c) 2006-2013 ARM Limited
rgrover1 712:b04b5db36865 3 *
rgrover1 712:b04b5db36865 4 * Licensed under the Apache License, Version 2.0 (the "License");
rgrover1 712:b04b5db36865 5 * you may not use this file except in compliance with the License.
rgrover1 712:b04b5db36865 6 * You may obtain a copy of the License at
rgrover1 712:b04b5db36865 7 *
rgrover1 712:b04b5db36865 8 * http://www.apache.org/licenses/LICENSE-2.0
rgrover1 712:b04b5db36865 9 *
rgrover1 712:b04b5db36865 10 * Unless required by applicable law or agreed to in writing, software
rgrover1 712:b04b5db36865 11 * distributed under the License is distributed on an "AS IS" BASIS,
rgrover1 712:b04b5db36865 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rgrover1 712:b04b5db36865 13 * See the License for the specific language governing permissions and
rgrover1 712:b04b5db36865 14 * limitations under the License.
rgrover1 712:b04b5db36865 15 */
rgrover1 712:b04b5db36865 16
rgrover1 712:b04b5db36865 17 #ifndef __BLE_UART_SERVICE_H__
rgrover1 712:b04b5db36865 18 #define __BLE_UART_SERVICE_H__
rgrover1 712:b04b5db36865 19
rgrover1 712:b04b5db36865 20 #include "mbed.h"
rgrover1 712:b04b5db36865 21 #include "Stream.h"
rgrover1 712:b04b5db36865 22
rgrover1 712:b04b5db36865 23 #include "ble/UUID.h"
rgrover1 712:b04b5db36865 24 #include "ble/BLE.h"
rgrover1 712:b04b5db36865 25
rgrover1 712:b04b5db36865 26 extern const uint8_t UARTServiceBaseUUID[UUID::LENGTH_OF_LONG_UUID];
rgrover1 712:b04b5db36865 27 extern const uint16_t UARTServiceShortUUID;
rgrover1 712:b04b5db36865 28 extern const uint16_t UARTServiceTXCharacteristicShortUUID;
rgrover1 712:b04b5db36865 29 extern const uint16_t UARTServiceRXCharacteristicShortUUID;
rgrover1 712:b04b5db36865 30
rgrover1 712:b04b5db36865 31 extern const uint8_t UARTServiceUUID[UUID::LENGTH_OF_LONG_UUID];
rgrover1 712:b04b5db36865 32 extern const uint8_t UARTServiceUUID_reversed[UUID::LENGTH_OF_LONG_UUID];
rgrover1 712:b04b5db36865 33
rgrover1 712:b04b5db36865 34 extern const uint8_t UARTServiceTXCharacteristicUUID[UUID::LENGTH_OF_LONG_UUID];
rgrover1 712:b04b5db36865 35 extern const uint8_t UARTServiceRXCharacteristicUUID[UUID::LENGTH_OF_LONG_UUID];
rgrover1 712:b04b5db36865 36
rgrover1 712:b04b5db36865 37 /**
rgrover1 712:b04b5db36865 38 * @class UARTService
rgrover1 712:b04b5db36865 39 * @brief BLE Service to enable UART over BLE
rgrover1 712:b04b5db36865 40 */
rgrover1 712:b04b5db36865 41 class UARTService {
rgrover1 712:b04b5db36865 42 public:
rgrover1 712:b04b5db36865 43 /**< Maximum length of data (in bytes) that can be transmitted by the UART service module to the peer. */
rgrover1 712:b04b5db36865 44 static const unsigned GATT_MTU_SIZE_DEFAULT = 23;
rgrover1 712:b04b5db36865 45 static const unsigned BLE_UART_SERVICE_MAX_DATA_LEN = (GATT_MTU_SIZE_DEFAULT - 3);
rgrover1 712:b04b5db36865 46
rgrover1 712:b04b5db36865 47 public:
rgrover1 712:b04b5db36865 48
rgrover1 712:b04b5db36865 49 /**
rgrover1 712:b04b5db36865 50 * @param[ref] ble
rgrover1 712:b04b5db36865 51 * BLE object for the underlying controller.
rgrover1 712:b04b5db36865 52 */
rgrover1 712:b04b5db36865 53 UARTService(BLE &_ble) :
rgrover1 712:b04b5db36865 54 ble(_ble),
rgrover1 712:b04b5db36865 55 receiveBuffer(),
rgrover1 712:b04b5db36865 56 sendBuffer(),
rgrover1 712:b04b5db36865 57 sendBufferIndex(0),
rgrover1 712:b04b5db36865 58 numBytesReceived(0),
rgrover1 712:b04b5db36865 59 receiveBufferIndex(0),
rgrover1 712:b04b5db36865 60 txCharacteristic(UARTServiceTXCharacteristicUUID, receiveBuffer, 1, BLE_UART_SERVICE_MAX_DATA_LEN,
rgrover1 712:b04b5db36865 61 GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE_WITHOUT_RESPONSE),
rgrover1 712:b04b5db36865 62 rxCharacteristic(UARTServiceRXCharacteristicUUID, sendBuffer, 1, BLE_UART_SERVICE_MAX_DATA_LEN, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY) {
rgrover1 712:b04b5db36865 63 GattCharacteristic *charTable[] = {&txCharacteristic, &rxCharacteristic};
rgrover1 712:b04b5db36865 64 GattService uartService(UARTServiceUUID, charTable, sizeof(charTable) / sizeof(GattCharacteristic *));
rgrover1 712:b04b5db36865 65
rgrover1 712:b04b5db36865 66 ble.addService(uartService);
rgrover1 712:b04b5db36865 67 ble.onDataWritten(this, &UARTService::onDataWritten);
rgrover1 712:b04b5db36865 68 }
rgrover1 712:b04b5db36865 69
rgrover1 712:b04b5db36865 70 /**
rgrover1 712:b04b5db36865 71 * Note: TX and RX characteristics are to be interpreted from the viewpoint of the GATT client using this service.
rgrover1 712:b04b5db36865 72 */
rgrover1 712:b04b5db36865 73 uint16_t getTXCharacteristicHandle() {
rgrover1 712:b04b5db36865 74 return txCharacteristic.getValueAttribute().getHandle();
rgrover1 712:b04b5db36865 75 }
rgrover1 712:b04b5db36865 76
rgrover1 712:b04b5db36865 77 /**
rgrover1 712:b04b5db36865 78 * Note: TX and RX characteristics are to be interpreted from the viewpoint of the GATT client using this service.
rgrover1 712:b04b5db36865 79 */
rgrover1 712:b04b5db36865 80 uint16_t getRXCharacteristicHandle() {
rgrover1 712:b04b5db36865 81 return rxCharacteristic.getValueAttribute().getHandle();
rgrover1 712:b04b5db36865 82 }
rgrover1 712:b04b5db36865 83
rgrover1 712:b04b5db36865 84 /**
rgrover1 712:b04b5db36865 85 * We attempt to collect bytes before pushing them to the UART RX
rgrover1 712:b04b5db36865 86 * characteristic--writing to the RX characteristic will then generate
rgrover1 712:b04b5db36865 87 * notifications for the client. Updates made in quick succession to a
rgrover1 712:b04b5db36865 88 * notification-generating characteristic will result in data being buffered
rgrover1 712:b04b5db36865 89 * in the bluetooth stack as notifications are sent out. The stack will have
rgrover1 712:b04b5db36865 90 * its limits for this buffering; typically a small number under 10.
rgrover1 712:b04b5db36865 91 * Collecting data into the sendBuffer buffer helps mitigate the rate of
rgrover1 712:b04b5db36865 92 * updates. But we shouldn't buffer a large amount of data before updating
rgrover1 712:b04b5db36865 93 * the characteristic otherwise the client will need to turn around and make
rgrover1 712:b04b5db36865 94 * a long read request; this is because notifications include only the first
rgrover1 712:b04b5db36865 95 * 20 bytes of the updated data.
rgrover1 712:b04b5db36865 96 *
rgrover1 712:b04b5db36865 97 * @param buffer The received update
rgrover1 712:b04b5db36865 98 * @param length Amount of characters to be appended.
rgrover1 712:b04b5db36865 99 * @return Amount of characters appended to the rxCharacteristic.
rgrover1 712:b04b5db36865 100 */
rgrover1 712:b04b5db36865 101 size_t write(const void *_buffer, size_t length) {
rgrover1 712:b04b5db36865 102 size_t origLength = length;
rgrover1 712:b04b5db36865 103 const uint8_t *buffer = static_cast<const uint8_t *>(_buffer);
rgrover1 712:b04b5db36865 104
rgrover1 712:b04b5db36865 105 if (ble.getGapState().connected) {
rgrover1 712:b04b5db36865 106 unsigned bufferIndex = 0;
rgrover1 712:b04b5db36865 107 while (length) {
rgrover1 712:b04b5db36865 108 unsigned bytesRemainingInSendBuffer = BLE_UART_SERVICE_MAX_DATA_LEN - sendBufferIndex;
rgrover1 712:b04b5db36865 109 unsigned bytesToCopy = (length < bytesRemainingInSendBuffer) ? length : bytesRemainingInSendBuffer;
rgrover1 712:b04b5db36865 110
rgrover1 712:b04b5db36865 111 /* copy bytes into sendBuffer */
rgrover1 712:b04b5db36865 112 memcpy(&sendBuffer[sendBufferIndex], &buffer[bufferIndex], bytesToCopy);
rgrover1 712:b04b5db36865 113 length -= bytesToCopy;
rgrover1 712:b04b5db36865 114 sendBufferIndex += bytesToCopy;
rgrover1 712:b04b5db36865 115 bufferIndex += bytesToCopy;
rgrover1 712:b04b5db36865 116
rgrover1 712:b04b5db36865 117 /* have we collected enough? */
rgrover1 712:b04b5db36865 118 if ((sendBufferIndex == BLE_UART_SERVICE_MAX_DATA_LEN) ||
rgrover1 712:b04b5db36865 119 // (sendBuffer[sendBufferIndex - 1] == '\r') ||
rgrover1 712:b04b5db36865 120 (sendBuffer[sendBufferIndex - 1] == '\n')) {
rgrover1 712:b04b5db36865 121 ble.updateCharacteristicValue(getRXCharacteristicHandle(), static_cast<const uint8_t *>(sendBuffer), sendBufferIndex);
rgrover1 712:b04b5db36865 122 sendBufferIndex = 0;
rgrover1 712:b04b5db36865 123 }
rgrover1 712:b04b5db36865 124 }
rgrover1 712:b04b5db36865 125 }
rgrover1 712:b04b5db36865 126
rgrover1 712:b04b5db36865 127 return origLength;
rgrover1 712:b04b5db36865 128 }
rgrover1 712:b04b5db36865 129
rgrover1 712:b04b5db36865 130 /**
rgrover1 712:b04b5db36865 131 * Helper function to write out strings.
rgrover1 712:b04b5db36865 132 * @param str The received string.
rgrover1 712:b04b5db36865 133 * @return Amount of characters appended to the rxCharacteristic.
rgrover1 712:b04b5db36865 134 */
rgrover1 712:b04b5db36865 135 size_t writeString(const char *str) {
rgrover1 712:b04b5db36865 136 return write(str, strlen(str));
rgrover1 712:b04b5db36865 137 }
rgrover1 712:b04b5db36865 138
rgrover1 712:b04b5db36865 139 /**
rgrover1 712:b04b5db36865 140 * Override for Stream::_putc()
rgrover1 712:b04b5db36865 141 * @param c
rgrover1 712:b04b5db36865 142 * This function writes the character c, cast to an unsigned char, to stream.
rgrover1 712:b04b5db36865 143 * @return
rgrover1 712:b04b5db36865 144 * The character written as an unsigned char cast to an int or EOF on error.
rgrover1 712:b04b5db36865 145 */
rgrover1 712:b04b5db36865 146 int _putc(int c) {
rgrover1 712:b04b5db36865 147 return (write(&c, 1) == 1) ? 1 : EOF;
rgrover1 712:b04b5db36865 148 }
rgrover1 712:b04b5db36865 149
rgrover1 712:b04b5db36865 150 /**
rgrover1 712:b04b5db36865 151 * Override for Stream::_getc()
rgrover1 712:b04b5db36865 152 * @return
rgrover1 712:b04b5db36865 153 * The character read.
rgrover1 712:b04b5db36865 154 */
rgrover1 712:b04b5db36865 155 int _getc() {
rgrover1 712:b04b5db36865 156 if (receiveBufferIndex == numBytesReceived) {
rgrover1 712:b04b5db36865 157 return EOF;
rgrover1 712:b04b5db36865 158 }
rgrover1 712:b04b5db36865 159
rgrover1 712:b04b5db36865 160 return receiveBuffer[receiveBufferIndex++];
rgrover1 712:b04b5db36865 161 }
rgrover1 712:b04b5db36865 162
rgrover1 712:b04b5db36865 163 private:
rgrover1 712:b04b5db36865 164 /**
rgrover1 712:b04b5db36865 165 * This callback allows the UART service to receive updates to the
rgrover1 712:b04b5db36865 166 * txCharacteristic. The application should forward the call to this
rgrover1 712:b04b5db36865 167 * function from the global onDataWritten() callback handler; or if that's
rgrover1 712:b04b5db36865 168 * not used, this method can be used as a callback directly.
rgrover1 712:b04b5db36865 169 */
rgrover1 712:b04b5db36865 170 void onDataWritten(const GattWriteCallbackParams *params) {
rgrover1 712:b04b5db36865 171 if (params->handle == getTXCharacteristicHandle()) {
rgrover1 712:b04b5db36865 172 uint16_t bytesRead = params->len;
rgrover1 712:b04b5db36865 173 if (bytesRead <= BLE_UART_SERVICE_MAX_DATA_LEN) {
rgrover1 712:b04b5db36865 174 numBytesReceived = bytesRead;
rgrover1 712:b04b5db36865 175 receiveBufferIndex = 0;
rgrover1 712:b04b5db36865 176 memcpy(receiveBuffer, params->data, numBytesReceived);
rgrover1 712:b04b5db36865 177 }
rgrover1 712:b04b5db36865 178 }
rgrover1 712:b04b5db36865 179 }
rgrover1 712:b04b5db36865 180
rgrover1 712:b04b5db36865 181 private:
rgrover1 712:b04b5db36865 182 BLE &ble;
rgrover1 712:b04b5db36865 183
rgrover1 712:b04b5db36865 184 uint8_t receiveBuffer[BLE_UART_SERVICE_MAX_DATA_LEN]; /**< The local buffer into which we receive
rgrover1 712:b04b5db36865 185 * inbound data before forwarding it to the
rgrover1 712:b04b5db36865 186 * application. */
rgrover1 712:b04b5db36865 187
rgrover1 712:b04b5db36865 188 uint8_t sendBuffer[BLE_UART_SERVICE_MAX_DATA_LEN]; /**< The local buffer into which outbound data is
rgrover1 712:b04b5db36865 189 * accumulated before being pushed to the
rgrover1 712:b04b5db36865 190 * rxCharacteristic. */
rgrover1 712:b04b5db36865 191 uint8_t sendBufferIndex;
rgrover1 712:b04b5db36865 192 uint8_t numBytesReceived;
rgrover1 712:b04b5db36865 193 uint8_t receiveBufferIndex;
rgrover1 712:b04b5db36865 194
rgrover1 712:b04b5db36865 195 GattCharacteristic txCharacteristic; /**< From the point of view of the external client, this is the characteristic
rgrover1 712:b04b5db36865 196 * they'd write into in order to communicate with this application. */
rgrover1 712:b04b5db36865 197 GattCharacteristic rxCharacteristic; /**< From the point of view of the external client, this is the characteristic
rgrover1 712:b04b5db36865 198 * they'd read from in order to receive the bytes transmitted by this
rgrover1 712:b04b5db36865 199 * application. */
rgrover1 712:b04b5db36865 200 };
rgrover1 712:b04b5db36865 201
rgrover1 712:b04b5db36865 202 #endif /* #ifndef __BLE_UART_SERVICE_H__*/