sen data via radio to other microbits accept command via radio bufixes
Dependencies: BLE_API nRF51822 mbed-dev-bin
Diff: source/drivers/MicroBitRadioDatagram.cpp
- Revision:
- 1:8aa5cdb4ab67
diff -r fb15f7887843 -r 8aa5cdb4ab67 source/drivers/MicroBitRadioDatagram.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/source/drivers/MicroBitRadioDatagram.cpp Thu Apr 07 01:33:22 2016 +0100 @@ -0,0 +1,203 @@ +/* +The MIT License (MIT) + +Copyright (c) 2016 British Broadcasting Corporation. +This software is provided by Lancaster University by arrangement with the BBC. + +Permission is hereby granted, free of charge, to any person obtaining a +copy of this software and associated documentation files (the "Software"), +to deal in the Software without restriction, including without limitation +the rights to use, copy, modify, merge, publish, distribute, sublicense, +and/or sell copies of the Software, and to permit persons to whom the +Software is furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL +THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING +FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. +*/ + +#include "MicroBitConfig.h" +#include "MicroBitRadio.h" + +/** + * Provides a simple broadcast radio abstraction, built upon the raw nrf51822 RADIO module. + * + * This class provides the ability to broadcast simple text or binary messages to other micro:bits in the vicinity + * It is envisaged that this would provide the basis for children to experiment with building their own, simple, + * custom protocols. + * + * @note This API does not contain any form of encryption, authentication or authorisation. Its purpose is solely for use as a + * teaching aid to demonstrate how simple communications operates, and to provide a sandpit through which learning can take place. + * For serious applications, BLE should be considered a substantially more secure alternative. + */ + +/** +* Constructor. +* +* Creates an instance of a MicroBitRadioDatagram which offers the ability +* to broadcast simple text or binary messages to other micro:bits in the vicinity +* +* @param r The underlying radio module used to send and receive data. +*/ +MicroBitRadioDatagram::MicroBitRadioDatagram(MicroBitRadio &r) : radio(r) +{ + this->rxQueue = NULL; +} + +/** + * Retrieves packet payload data into the given buffer. + * + * If a data packet is already available, then it will be returned immediately to the caller. + * If no data is available then MICROBIT_INVALID_PARAMETER is returned. + * + * @param buf A pointer to a valid memory location where the received data is to be stored + * + * @param len The maximum amount of data that can safely be stored in 'buf' + * + * @return The length of the data stored, or MICROBIT_INVALID_PARAMETER if no data is available, or the memory regions provided are invalid. + */ +int MicroBitRadioDatagram::recv(uint8_t *buf, int len) +{ + if (buf == NULL || rxQueue == NULL || len < 0) + return MICROBIT_INVALID_PARAMETER; + + // Take the first buffer from the queue. + FrameBuffer *p = rxQueue; + rxQueue = rxQueue->next; + + int l = min(len, p->length - (MICROBIT_RADIO_HEADER_SIZE - 1)); + + // Fill in the buffer provided, if possible. + memcpy(buf, p->payload, l); + + delete p; + return l; +} + +/** + * Retreives packet payload data into the given buffer. + * + * If a data packet is already available, then it will be returned immediately to the caller + * in the form of a PacketBuffer. + * + * @return the data received, or an empty PacketBuffer if no data is available. + */ +PacketBuffer MicroBitRadioDatagram::recv() +{ + if (rxQueue == NULL) + return PacketBuffer::EmptyPacket; + + FrameBuffer *p = rxQueue; + rxQueue = rxQueue->next; + + PacketBuffer packet(p->payload, p->length - (MICROBIT_RADIO_HEADER_SIZE - 1), p->rssi); + + delete p; + return packet; +} + +/** + * Transmits the given buffer onto the broadcast radio. + * + * This is a synchronous call that will wait until the transmission of the packet + * has completed before returning. + * + * @param buffer The packet contents to transmit. + * + * @param len The number of bytes to transmit. + * + * @return MICROBIT_OK on success, or MICROBIT_INVALID_PARAMETER if the buffer is invalid, + * or the number of bytes to transmit is greater than `MICROBIT_RADIO_MAX_PACKET_SIZE + MICROBIT_RADIO_HEADER_SIZE`. + */ +int MicroBitRadioDatagram::send(uint8_t *buffer, int len) +{ + if (buffer == NULL || len < 0 || len > MICROBIT_RADIO_MAX_PACKET_SIZE + MICROBIT_RADIO_HEADER_SIZE - 1) + return MICROBIT_INVALID_PARAMETER; + + FrameBuffer buf; + + buf.length = len + MICROBIT_RADIO_HEADER_SIZE - 1; + buf.version = 1; + buf.group = 0; + buf.protocol = MICROBIT_RADIO_PROTOCOL_DATAGRAM; + memcpy(buf.payload, buffer, len); + + return radio.send(&buf); +} + +/** + * Transmits the given string onto the broadcast radio. + * + * This is a synchronous call that will wait until the transmission of the packet + * has completed before returning. + * + * @param data The packet contents to transmit. + * + * @return MICROBIT_OK on success, or MICROBIT_INVALID_PARAMETER if the buffer is invalid, + * or the number of bytes to transmit is greater than `MICROBIT_RADIO_MAX_PACKET_SIZE + MICROBIT_RADIO_HEADER_SIZE`. + */ +int MicroBitRadioDatagram::send(PacketBuffer data) +{ + return send((uint8_t *)data.getBytes(), data.length()); +} + +/** + * Transmits the given string onto the broadcast radio. + * + * This is a synchronous call that will wait until the transmission of the packet + * has completed before returning. + * + * @param data The packet contents to transmit. + * + * @return MICROBIT_OK on success, or MICROBIT_INVALID_PARAMETER if the buffer is invalid, + * or the number of bytes to transmit is greater than `MICROBIT_RADIO_MAX_PACKET_SIZE + MICROBIT_RADIO_HEADER_SIZE`. + */ +int MicroBitRadioDatagram::send(ManagedString data) +{ + return send((uint8_t *)data.toCharArray(), data.length()); +} + +/** + * Protocol handler callback. This is called when the radio receives a packet marked as a datagram. + * + * This function process this packet, and queues it for user reception. + */ +void MicroBitRadioDatagram::packetReceived() +{ + FrameBuffer *packet = radio.recv(); + int queueDepth = 0; + + // We add to the tail of the queue to preserve causal ordering. + packet->next = NULL; + + if (rxQueue == NULL) + { + rxQueue = packet; + } + else + { + FrameBuffer *p = rxQueue; + while (p->next != NULL) + { + p = p->next; + queueDepth++; + } + + if (queueDepth >= MICROBIT_RADIO_MAXIMUM_RX_BUFFERS) + { + delete packet; + return; + } + + p->next = packet; + } + + MicroBitEvent(MICROBIT_ID_RADIO, MICROBIT_RADIO_EVT_DATAGRAM); +}