BLE lib
Fork of Nucleo_BLE_API by
services/UARTService.h
- Committer:
- sjallouli
- Date:
- 2014-12-19
- Revision:
- 0:289fd2dae405
- Child:
- 1:79e5c08cbcc7
File content as of revision 0:289fd2dae405:
/* 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__ #include "Stream.h" #include "UUID.h" #include "BLEDevice.h" extern const uint8_t UARTServiceBaseUUID[LENGTH_OF_LONG_UUID]; extern const uint16_t UARTServiceShortUUID; extern const uint16_t UARTServiceTXCharacteristicShortUUID; extern const uint16_t UARTServiceRXCharacteristicShortUUID; extern const uint8_t UARTServiceUUID[LENGTH_OF_LONG_UUID]; extern const uint8_t UARTServiceUUID_reversed[LENGTH_OF_LONG_UUID]; extern const uint8_t UARTServiceTXCharacteristicUUID[LENGTH_OF_LONG_UUID]; extern const uint8_t UARTServiceRXCharacteristicUUID[LENGTH_OF_LONG_UUID]; class UARTService : public Stream { public: /**< Maximum length of data (in bytes) that can be transmitted by the UART service module to the peer. */ static const unsigned GATT_MTU_SIZE_DEFAULT = 23; static const unsigned BLE_UART_SERVICE_MAX_DATA_LEN = (GATT_MTU_SIZE_DEFAULT - 3); public: UARTService(BLEDevice &_ble) : Stream("blueart"), 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(); } /** * Following a call to this function, all writes to stdout (such as from * printf) get redirected to the outbound characteristic of this service. * This might be very useful when wanting to receive debug messages over BLE. * * @Note: debug messages originating from printf() like calls are buffered * before being sent out. A '\n' in the printf() triggers the buffer update * to the underlying characteristic. * * @Note: long messages need to be chopped up into 20-byte updates so that * they flow out completely with notifications. The receiver should be * prepared to stitch these messages back. */ void retargetStdout() { freopen("/blueart", "w", stdout); } /** * 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; or if that's * not used, this method can be used as a callback directly. */ virtual void onDataWritten(const GattCharacteristicWriteCBParams *params) { if (params->charHandle == getTXCharacteristicHandle()) { uint16_t bytesRead = params->len; if (bytesRead <= BLE_UART_SERVICE_MAX_DATA_LEN) { numBytesReceived = bytesRead; receiveBufferIndex = 0; memcpy(receiveBuffer, params->data, numBytesReceived); } } } protected: /** * Override for Stream::write(). * * We attempt to collect bytes before pushing them to the UART RX * characteristic--writing to the RX characteristic will then generate * notifications for the client. Updates made in quick succession to a * notification-generating characteristic will result in data being buffered * in the bluetooth stack as notifications are sent out. The stack will have * 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 will need 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 Amount of characters to be appended. * @return Amount of characters appended to the rxCharacteristic. */ virtual ssize_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.updateCharacteristicValue(getRXCharacteristicHandle(), static_cast<const uint8_t *>(sendBuffer), sendBufferIndex); sendBufferIndex = 0; } } } return origLength; } /** * 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. */ virtual int _putc(int c) { return (write(&c, 1) == 1) ? 1 : EOF; } virtual int _getc() { if (receiveBufferIndex == numBytesReceived) { return EOF; } return receiveBuffer[receiveBufferIndex++]; } virtual int isatty() { return 1; } private: BLEDevice &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__*/