High level Bluetooth Low Energy API and radio abstraction layer
Fork of BLE_API by
ble/services/UARTService.h
- Committer:
- Vincent Coubard
- Date:
- 2016-09-14
- Revision:
- 1208:65474dc93927
- Parent:
- 1053:ec4a5b9b254e
File content as of revision 1208:65474dc93927:
/* 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_UART_SERVICE_H__ #define __BLE_UART_SERVICE_H__ #ifdef YOTTA_CFG_MBED_OS #include "mbed-drivers/mbed.h" #include "mbed-drivers/Stream.h" #else #include "mbed.h" #include "Stream.h" #endif #include "ble/UUID.h" #include "ble/BLE.h" extern const uint8_t UARTServiceBaseUUID[UUID::LENGTH_OF_LONG_UUID]; extern const uint16_t UARTServiceShortUUID; extern const uint16_t UARTServiceTXCharacteristicShortUUID; extern const uint16_t UARTServiceRXCharacteristicShortUUID; extern const uint8_t UARTServiceUUID[UUID::LENGTH_OF_LONG_UUID]; extern const uint8_t UARTServiceUUID_reversed[UUID::LENGTH_OF_LONG_UUID]; extern const uint8_t UARTServiceTXCharacteristicUUID[UUID::LENGTH_OF_LONG_UUID]; extern const uint8_t UARTServiceRXCharacteristicUUID[UUID::LENGTH_OF_LONG_UUID]; /** * @class UARTService. * @brief BLE Service to enable UART over BLE. */ class UARTService { public: /**< Maximum length of data (in bytes) that the UART service module can transmit to the peer. */ static const unsigned BLE_UART_SERVICE_MAX_DATA_LEN = (BLE_GATT_MTU_SIZE_DEFAULT - 3); public: /** * @param[ref] ble * BLE object for the underlying controller. */ UARTService(BLE &_ble) : ble(_ble), receiveBuffer(), sendBuffer(), sendBufferIndex(0), numBytesReceived(0), receiveBufferIndex(0), txCharacteristic(UARTServiceTXCharacteristicUUID, receiveBuffer, 1, BLE_UART_SERVICE_MAX_DATA_LEN, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE_WITHOUT_RESPONSE), rxCharacteristic(UARTServiceRXCharacteristicUUID, sendBuffer, 1, BLE_UART_SERVICE_MAX_DATA_LEN, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY) { GattCharacteristic *charTable[] = {&txCharacteristic, &rxCharacteristic}; GattService uartService(UARTServiceUUID, charTable, sizeof(charTable) / sizeof(GattCharacteristic *)); ble.addService(uartService); ble.onDataWritten(this, &UARTService::onDataWritten); } /** * Note: TX and RX characteristics are to be interpreted from the viewpoint of the GATT client using this service. */ uint16_t getTXCharacteristicHandle() { return txCharacteristic.getValueAttribute().getHandle(); } /** * Note: TX and RX characteristics are to be interpreted from the viewpoint of the GATT client using this service. */ uint16_t getRXCharacteristicHandle() { return rxCharacteristic.getValueAttribute().getHandle(); } /** * We attempt to collect bytes before pushing them to the UART RX * characteristic; writing to the RX characteristic then generates * notifications for the client. Updates made in quick succession to a * notification-generating characteristic result in data being buffered * in the Bluetooth stack as notifications are sent out. The stack has * its limits for this buffering - typically a small number under 10. * Collecting data into the sendBuffer buffer helps mitigate the rate of * updates. But we shouldn't buffer a large amount of data before updating * the characteristic, otherwise the client needs to turn around and make * a long read request; this is because notifications include only the first * 20 bytes of the updated data. * * @param buffer The received update. * @param length Number of characters to be appended. * @return Number of characters appended to the rxCharacteristic. */ size_t write(const void *_buffer, size_t length) { size_t origLength = length; const uint8_t *buffer = static_cast<const uint8_t *>(_buffer); if (ble.getGapState().connected) { unsigned bufferIndex = 0; while (length) { unsigned bytesRemainingInSendBuffer = BLE_UART_SERVICE_MAX_DATA_LEN - sendBufferIndex; unsigned bytesToCopy = (length < bytesRemainingInSendBuffer) ? length : bytesRemainingInSendBuffer; /* Copy bytes into sendBuffer. */ memcpy(&sendBuffer[sendBufferIndex], &buffer[bufferIndex], bytesToCopy); length -= bytesToCopy; sendBufferIndex += bytesToCopy; bufferIndex += bytesToCopy; /* Have we collected enough? */ if ((sendBufferIndex == BLE_UART_SERVICE_MAX_DATA_LEN) || // (sendBuffer[sendBufferIndex - 1] == '\r') || (sendBuffer[sendBufferIndex - 1] == '\n')) { ble.gattServer().write(getRXCharacteristicHandle(), static_cast<const uint8_t *>(sendBuffer), sendBufferIndex); sendBufferIndex = 0; } } } return origLength; } /** * Helper function to write out strings. * @param str The received string. * @return Number of characters appended to the rxCharacteristic. */ size_t writeString(const char *str) { return write(str, strlen(str)); } /** * Override for Stream::_putc(). * @param c * This function writes the character c, cast to an unsigned char, to stream. * @return * The character written as an unsigned char cast to an int or EOF on error. */ int _putc(int c) { return (write(&c, 1) == 1) ? 1 : EOF; } /** * Override for Stream::_getc(). * @return * The character read. */ int _getc() { if (receiveBufferIndex == numBytesReceived) { return EOF; } return receiveBuffer[receiveBufferIndex++]; } protected: /** * This callback allows the UART service to receive updates to the * txCharacteristic. The application should forward the call to this * function from the global onDataWritten() callback handler; if that's * not used, this method can be used as a callback directly. */ void onDataWritten(const GattWriteCallbackParams *params) { if (params->handle == getTXCharacteristicHandle()) { uint16_t bytesRead = params->len; if (bytesRead <= BLE_UART_SERVICE_MAX_DATA_LEN) { numBytesReceived = bytesRead; receiveBufferIndex = 0; memcpy(receiveBuffer, params->data, numBytesReceived); } } } protected: BLE &ble; uint8_t receiveBuffer[BLE_UART_SERVICE_MAX_DATA_LEN]; /**< The local buffer into which we receive * inbound data before forwarding it to the * application. */ uint8_t sendBuffer[BLE_UART_SERVICE_MAX_DATA_LEN]; /**< The local buffer into which outbound data is * accumulated before being pushed to the * rxCharacteristic. */ uint8_t sendBufferIndex; uint8_t numBytesReceived; uint8_t receiveBufferIndex; GattCharacteristic txCharacteristic; /**< From the point of view of the external client, this is the characteristic * they'd write into in order to communicate with this application. */ GattCharacteristic rxCharacteristic; /**< From the point of view of the external client, this is the characteristic * they'd read from in order to receive the bytes transmitted by this * application. */ }; #endif /* #ifndef __BLE_UART_SERVICE_H__*/