Bill Schilit / BLE_API

Improve readability with getHandle inline

Fork of BLE_API by Bluetooth Low Energy

services/UARTService.h@197:5551036f054b, 2014-11-28 (annotated)

Committer:
rgrover1
Date:
Fri Nov 28 14:11:25 2014 +0000
Revision:
197:5551036f054b
Parent:
195:7c0c8ba69626
Child:
198:933961a2ac6f
Synchronized with git rev 959ba7c6

Author: Rohit Grover

removing Stream as a base class for UARTService.

Instantiating Stream was causing a call to initialize the serial console uart; which caused a constant drain of around 1mA.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Rohit Grover 118:620d28e7a1ba 1 /* mbed Microcontroller Library
Rohit Grover 118:620d28e7a1ba 2 * Copyright (c) 2006-2013 ARM Limited
Rohit Grover 118:620d28e7a1ba 3 *
Rohit Grover 118:620d28e7a1ba 4 * Licensed under the Apache License, Version 2.0 (the "License");
Rohit Grover 118:620d28e7a1ba 5 * you may not use this file except in compliance with the License.
Rohit Grover 118:620d28e7a1ba 6 * You may obtain a copy of the License at
Rohit Grover 118:620d28e7a1ba 7 *
Rohit Grover 118:620d28e7a1ba 8 * http://www.apache.org/licenses/LICENSE-2.0
Rohit Grover 118:620d28e7a1ba 9 *
Rohit Grover 118:620d28e7a1ba 10 * Unless required by applicable law or agreed to in writing, software
Rohit Grover 118:620d28e7a1ba 11 * distributed under the License is distributed on an "AS IS" BASIS,
Rohit Grover 118:620d28e7a1ba 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
Rohit Grover 118:620d28e7a1ba 13 * See the License for the specific language governing permissions and
Rohit Grover 118:620d28e7a1ba 14 * limitations under the License.
Rohit Grover 118:620d28e7a1ba 15 */
Rohit Grover 118:620d28e7a1ba 16
Rohit Grover 118:620d28e7a1ba 17 #ifndef __BLE_UART_SERVICE_H__
Rohit Grover 118:620d28e7a1ba 18 #define __BLE_UART_SERVICE_H__
Rohit Grover 118:620d28e7a1ba 19
Rohit Grover 118:620d28e7a1ba 20 #include "Stream.h"
Rohit Grover 118:620d28e7a1ba 21
Rohit Grover 118:620d28e7a1ba 22 #include "UUID.h"
Rohit Grover 118:620d28e7a1ba 23 #include "BLEDevice.h"
Rohit Grover 118:620d28e7a1ba 24
Rohit Grover 118:620d28e7a1ba 25 extern const uint8_t UARTServiceBaseUUID[LENGTH_OF_LONG_UUID];
Rohit Grover 118:620d28e7a1ba 26 extern const uint16_t UARTServiceShortUUID;
Rohit Grover 118:620d28e7a1ba 27 extern const uint16_t UARTServiceTXCharacteristicShortUUID;
Rohit Grover 118:620d28e7a1ba 28 extern const uint16_t UARTServiceRXCharacteristicShortUUID;
Rohit Grover 118:620d28e7a1ba 29
Rohit Grover 118:620d28e7a1ba 30 extern const uint8_t UARTServiceUUID[LENGTH_OF_LONG_UUID];
Rohit Grover 118:620d28e7a1ba 31 extern const uint8_t UARTServiceUUID_reversed[LENGTH_OF_LONG_UUID];
Rohit Grover 118:620d28e7a1ba 32
Rohit Grover 118:620d28e7a1ba 33 extern const uint8_t UARTServiceTXCharacteristicUUID[LENGTH_OF_LONG_UUID];
Rohit Grover 118:620d28e7a1ba 34 extern const uint8_t UARTServiceRXCharacteristicUUID[LENGTH_OF_LONG_UUID];
Rohit Grover 118:620d28e7a1ba 35
rgrover1 197:5551036f054b 36 class UARTService {
Rohit Grover 118:620d28e7a1ba 37 public:
Rohit Grover 118:620d28e7a1ba 38 /**< Maximum length of data (in bytes) that can be transmitted by the UART service module to the peer. */
rgrover1 197:5551036f054b 39 static const unsigned GATT_MTU_SIZE_DEFAULT = 23;
Rohit Grover 118:620d28e7a1ba 40 static const unsigned BLE_UART_SERVICE_MAX_DATA_LEN = (GATT_MTU_SIZE_DEFAULT - 3);
Rohit Grover 118:620d28e7a1ba 41
Rohit Grover 118:620d28e7a1ba 42 public:
Rohit Grover 118:620d28e7a1ba 43 UARTService(BLEDevice &_ble) :
Rohit Grover 118:620d28e7a1ba 44 ble(_ble),
Rohit Grover 118:620d28e7a1ba 45 receiveBuffer(),
Rohit Grover 118:620d28e7a1ba 46 sendBuffer(),
Rohit Grover 118:620d28e7a1ba 47 sendBufferIndex(0),
Rohit Grover 118:620d28e7a1ba 48 numBytesReceived(0),
Rohit Grover 118:620d28e7a1ba 49 receiveBufferIndex(0),
Rohit Grover 118:620d28e7a1ba 50 txCharacteristic(UARTServiceTXCharacteristicUUID, receiveBuffer, 1, BLE_UART_SERVICE_MAX_DATA_LEN,
Rohit Grover 118:620d28e7a1ba 51 GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE_WITHOUT_RESPONSE),
Rohit Grover 118:620d28e7a1ba 52 rxCharacteristic(UARTServiceRXCharacteristicUUID, sendBuffer, 1, BLE_UART_SERVICE_MAX_DATA_LEN, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY) {
Rohit Grover 118:620d28e7a1ba 53 GattCharacteristic *charTable[] = {&txCharacteristic, &rxCharacteristic};
Rohit Grover 118:620d28e7a1ba 54 GattService uartService(UARTServiceUUID, charTable, sizeof(charTable) / sizeof(GattCharacteristic *));
Rohit Grover 118:620d28e7a1ba 55
Rohit Grover 118:620d28e7a1ba 56 ble.addService(uartService);
Rohit Grover 118:620d28e7a1ba 57 ble.onDataWritten(this, &UARTService::onDataWritten);
Rohit Grover 118:620d28e7a1ba 58 }
Rohit Grover 118:620d28e7a1ba 59
Rohit Grover 118:620d28e7a1ba 60 /**
Rohit Grover 118:620d28e7a1ba 61 * Note: TX and RX characteristics are to be interpreted from the viewpoint of the GATT client using this service.
Rohit Grover 118:620d28e7a1ba 62 */
Rohit Grover 118:620d28e7a1ba 63 uint16_t getTXCharacteristicHandle() {
Rohit Grover 118:620d28e7a1ba 64 return txCharacteristic.getValueAttribute().getHandle();
Rohit Grover 118:620d28e7a1ba 65 }
Rohit Grover 118:620d28e7a1ba 66
Rohit Grover 118:620d28e7a1ba 67 /**
Rohit Grover 118:620d28e7a1ba 68 * Note: TX and RX characteristics are to be interpreted from the viewpoint of the GATT client using this service.
Rohit Grover 118:620d28e7a1ba 69 */
Rohit Grover 118:620d28e7a1ba 70 uint16_t getRXCharacteristicHandle() {
Rohit Grover 118:620d28e7a1ba 71 return rxCharacteristic.getValueAttribute().getHandle();
Rohit Grover 118:620d28e7a1ba 72 }
Rohit Grover 118:620d28e7a1ba 73
Rohit Grover 118:620d28e7a1ba 74 /**
Rohit Grover 118:620d28e7a1ba 75 * Override for Stream::write().
Rohit Grover 118:620d28e7a1ba 76 *
Rohit Grover 118:620d28e7a1ba 77 * We attempt to collect bytes before pushing them to the UART RX
Rohit Grover 118:620d28e7a1ba 78 * characteristic--writing to the RX characteristic will then generate
Rohit Grover 118:620d28e7a1ba 79 * notifications for the client. Updates made in quick succession to a
Rohit Grover 118:620d28e7a1ba 80 * notification-generating characteristic will result in data being buffered
Rohit Grover 118:620d28e7a1ba 81 * in the bluetooth stack as notifications are sent out. The stack will have
Rohit Grover 118:620d28e7a1ba 82 * its limits for this buffering; typically a small number under 10.
Rohit Grover 118:620d28e7a1ba 83 * Collecting data into the sendBuffer buffer helps mitigate the rate of
Rohit Grover 118:620d28e7a1ba 84 * updates. But we shouldn't buffer a large amount of data before updating
Rohit Grover 118:620d28e7a1ba 85 * the characteristic otherwise the client will need to turn around and make
Rohit Grover 118:620d28e7a1ba 86 * a long read request; this is because notifications include only the first
Rohit Grover 118:620d28e7a1ba 87 * 20 bytes of the updated data.
Rohit Grover 118:620d28e7a1ba 88 *
Rohit Grover 118:620d28e7a1ba 89 * @param buffer The received update
Rohit Grover 118:620d28e7a1ba 90 * @param length Amount of characters to be appended.
Rohit Grover 118:620d28e7a1ba 91 * @return Amount of characters appended to the rxCharacteristic.
Rohit Grover 118:620d28e7a1ba 92 */
rgrover1 197:5551036f054b 93 ssize_t write(const void* _buffer, size_t length) {
Rohit Grover 118:620d28e7a1ba 94 size_t origLength = length;
Rohit Grover 118:620d28e7a1ba 95 const uint8_t *buffer = static_cast<const uint8_t *>(_buffer);
Rohit Grover 118:620d28e7a1ba 96
Rohit Grover 118:620d28e7a1ba 97 if (ble.getGapState().connected) {
Rohit Grover 118:620d28e7a1ba 98 unsigned bufferIndex = 0;
Rohit Grover 118:620d28e7a1ba 99 while (length) {
Rohit Grover 118:620d28e7a1ba 100 unsigned bytesRemainingInSendBuffer = BLE_UART_SERVICE_MAX_DATA_LEN - sendBufferIndex;
Rohit Grover 118:620d28e7a1ba 101 unsigned bytesToCopy = (length < bytesRemainingInSendBuffer) ? length : bytesRemainingInSendBuffer;
Rohit Grover 118:620d28e7a1ba 102
Rohit Grover 118:620d28e7a1ba 103 /* copy bytes into sendBuffer */
Rohit Grover 118:620d28e7a1ba 104 memcpy(&sendBuffer[sendBufferIndex], &buffer[bufferIndex], bytesToCopy);
Rohit Grover 118:620d28e7a1ba 105 length -= bytesToCopy;
Rohit Grover 118:620d28e7a1ba 106 sendBufferIndex += bytesToCopy;
Rohit Grover 118:620d28e7a1ba 107 bufferIndex += bytesToCopy;
Rohit Grover 118:620d28e7a1ba 108
Rohit Grover 118:620d28e7a1ba 109 /* have we collected enough? */
Rohit Grover 118:620d28e7a1ba 110 if ((sendBufferIndex == BLE_UART_SERVICE_MAX_DATA_LEN) ||
Rohit Grover 118:620d28e7a1ba 111 // (sendBuffer[sendBufferIndex - 1] == '\r') ||
Rohit Grover 118:620d28e7a1ba 112 (sendBuffer[sendBufferIndex - 1] == '\n')) {
Rohit Grover 118:620d28e7a1ba 113 ble.updateCharacteristicValue(getRXCharacteristicHandle(), static_cast<const uint8_t *>(sendBuffer), sendBufferIndex);
Rohit Grover 118:620d28e7a1ba 114 sendBufferIndex = 0;
Rohit Grover 118:620d28e7a1ba 115 }
Rohit Grover 118:620d28e7a1ba 116 }
Rohit Grover 118:620d28e7a1ba 117 }
Rohit Grover 118:620d28e7a1ba 118
Rohit Grover 118:620d28e7a1ba 119 return origLength;
Rohit Grover 118:620d28e7a1ba 120 }
Rohit Grover 118:620d28e7a1ba 121
Rohit Grover 118:620d28e7a1ba 122 /**
Rohit Grover 118:620d28e7a1ba 123 * Override for Stream::_putc()
Rohit Grover 118:620d28e7a1ba 124 * @param c
Rohit Grover 118:620d28e7a1ba 125 * This function writes the character c, cast to an unsigned char, to stream.
Rohit Grover 118:620d28e7a1ba 126 * @return
Rohit Grover 118:620d28e7a1ba 127 * The character written as an unsigned char cast to an int or EOF on error.
Rohit Grover 118:620d28e7a1ba 128 */
rgrover1 197:5551036f054b 129 int _putc(int c) {
Rohit Grover 118:620d28e7a1ba 130 return (write(&c, 1) == 1) ? 1 : EOF;
Rohit Grover 118:620d28e7a1ba 131 }
Rohit Grover 118:620d28e7a1ba 132
rgrover1 197:5551036f054b 133 int _getc() {
Rohit Grover 118:620d28e7a1ba 134 if (receiveBufferIndex == numBytesReceived) {
Rohit Grover 118:620d28e7a1ba 135 return EOF;
Rohit Grover 118:620d28e7a1ba 136 }
Rohit Grover 118:620d28e7a1ba 137
Rohit Grover 118:620d28e7a1ba 138 return receiveBuffer[receiveBufferIndex++];
Rohit Grover 118:620d28e7a1ba 139 }
Rohit Grover 118:620d28e7a1ba 140
rgrover1 197:5551036f054b 141 private:
rgrover1 197:5551036f054b 142 /**
rgrover1 197:5551036f054b 143 * This callback allows the UART service to receive updates to the
rgrover1 197:5551036f054b 144 * txCharacteristic. The application should forward the call to this
rgrover1 197:5551036f054b 145 * function from the global onDataWritten() callback handler; or if that's
rgrover1 197:5551036f054b 146 * not used, this method can be used as a callback directly.
rgrover1 197:5551036f054b 147 */
rgrover1 197:5551036f054b 148 void onDataWritten(const GattCharacteristicWriteCBParams *params) {
rgrover1 197:5551036f054b 149 if (params->charHandle == getTXCharacteristicHandle()) {
rgrover1 197:5551036f054b 150 uint16_t bytesRead = params->len;
rgrover1 197:5551036f054b 151 if (bytesRead <= BLE_UART_SERVICE_MAX_DATA_LEN) {
rgrover1 197:5551036f054b 152 numBytesReceived = bytesRead;
rgrover1 197:5551036f054b 153 receiveBufferIndex = 0;
rgrover1 197:5551036f054b 154 memcpy(receiveBuffer, params->data, numBytesReceived);
rgrover1 197:5551036f054b 155 }
rgrover1 197:5551036f054b 156 }
Rohit Grover 118:620d28e7a1ba 157 }
Rohit Grover 118:620d28e7a1ba 158
Rohit Grover 118:620d28e7a1ba 159 private:
Rohit Grover 118:620d28e7a1ba 160 BLEDevice &ble;
Rohit Grover 118:620d28e7a1ba 161
Rohit Grover 118:620d28e7a1ba 162 uint8_t receiveBuffer[BLE_UART_SERVICE_MAX_DATA_LEN]; /**< The local buffer into which we receive
Rohit Grover 118:620d28e7a1ba 163 * inbound data before forwarding it to the
Rohit Grover 118:620d28e7a1ba 164 * application. */
Rohit Grover 118:620d28e7a1ba 165
Rohit Grover 118:620d28e7a1ba 166 uint8_t sendBuffer[BLE_UART_SERVICE_MAX_DATA_LEN]; /**< The local buffer into which outbound data is
Rohit Grover 118:620d28e7a1ba 167 * accumulated before being pushed to the
Rohit Grover 118:620d28e7a1ba 168 * rxCharacteristic. */
Rohit Grover 118:620d28e7a1ba 169 uint8_t sendBufferIndex;
Rohit Grover 118:620d28e7a1ba 170 uint8_t numBytesReceived;
Rohit Grover 118:620d28e7a1ba 171 uint8_t receiveBufferIndex;
Rohit Grover 118:620d28e7a1ba 172
Rohit Grover 118:620d28e7a1ba 173 GattCharacteristic txCharacteristic; /**< From the point of view of the external client, this is the characteristic
Rohit Grover 118:620d28e7a1ba 174 * they'd write into in order to communicate with this application. */
Rohit Grover 118:620d28e7a1ba 175 GattCharacteristic rxCharacteristic; /**< From the point of view of the external client, this is the characteristic
Rohit Grover 118:620d28e7a1ba 176 * they'd read from in order to receive the bytes transmitted by this
Rohit Grover 118:620d28e7a1ba 177 * application. */
Rohit Grover 118:620d28e7a1ba 178 };
Rohit Grover 118:620d28e7a1ba 179
Rohit Grover 118:620d28e7a1ba 180 #endif /* #ifndef __BLE_UART_SERVICE_H__*/