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93901e8754
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@199 ebee16cc-31ac-478f-84a7-5cbb03baadba
479 lines
14 KiB
C
479 lines
14 KiB
C
/**
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******************************************************************************
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*
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* @file uavtalk.c
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* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
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* @brief UAVTalk library, implements to telemetry protocol. See the wiki for more details.
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* This library should not be called directly by the application, it is only used by the
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* Telemetry module.
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* @see The GNU Public License (GPL) Version 3
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*
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*****************************************************************************/
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/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "uavtalk.h"
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#include "FreeRTOS.h"
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#include "semphr.h"
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// Private constants
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#define TYPE_MASK 0xFC
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#define TYPE_VER 0x10
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#define TYPE_OBJ (TYPE_VER | 0x00)
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#define TYPE_OBJ_REQ (TYPE_VER | 0x01)
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#define TYPE_OBJ_ACK (TYPE_VER | 0x02)
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#define TYPE_ACK (TYPE_VER | 0x03)
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#define HEADER_LENGTH 6 // type (1), object ID (4), length (1)
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#define CHECKSUM_LENGTH 2
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#define MAX_PAYLOAD_LENGTH 256
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#define MAX_PACKET_LENGTH (HEADER_LENGTH+MAX_PAYLOAD_LENGTH+CHECKSUM_LENGTH)
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#define MAX_UPDATE_PERIOD_MS 1000
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#define MIN_UPDATE_PERIOD_MS 1
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// Private types
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typedef enum {STATE_SYNC, STATE_OBJID, STATE_INSTID, STATE_DATA, STATE_CS} RxState;
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// Private variables
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UAVTalkOutputStream outStream;
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xSemaphoreHandle lock;
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xSemaphoreHandle respSema;
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UAVObjHandle respObj;
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uint16_t respInstId;
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uint8_t rxBuffer[MAX_PACKET_LENGTH];
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uint8_t txBuffer[MAX_PACKET_LENGTH];
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// Private functions
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uint16_t updateChecksum(uint16_t cs, uint8_t* data, int32_t length);
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int32_t objectTransaction(uint32_t objectId, uint16_t instId, uint8_t type, int32_t timeout);
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int32_t sendObject(UAVObjHandle obj, uint16_t instId, uint8_t type);
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int32_t sendSingleObject(UAVObjHandle obj, uint16_t instId, uint8_t type);
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int32_t receiveObject(uint8_t type, UAVObjHandle obj, uint16_t instId, uint8_t* data, int32_t length);
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/**
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* Initialize the UAVTalk library
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* \param[in] outputStream Function pointer that is called to send a data buffer
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* \return 0 Success
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* \return -1 Failure
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*/
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int32_t UAVTalkInitialize(UAVTalkOutputStream outputStream)
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{
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outStream = outputStream;
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lock = xSemaphoreCreateRecursiveMutex();
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vSemaphoreCreateBinary(respSema);
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return 0;
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}
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/**
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* Request an update for the specified object, on success the object data would have been
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* updated by the GCS.
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* \param[in] obj Object to update
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* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
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* \param[in] timeout Time to wait for the response, when zero it will return immediately
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* \return 0 Success
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* \return -1 Failure
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*/
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int32_t UAVTalkSendObjectRequest(UAVObjHandle obj, uint16_t instId, int32_t timeout)
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{
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return objectTransaction(obj, instId, TYPE_OBJ_REQ, timeout);
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}
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/**
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* Send the specified object through the telemetry link.
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* \param[in] obj Object to send
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* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
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* \param[in] acked Selects if an ack is required (1:ack required, 0: ack not required)
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* \param[in] timeoutMs Time to wait for the ack, when zero it will return immediately
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* \return 0 Success
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* \return -1 Failure
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*/
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int32_t UAVTalkSendObject(UAVObjHandle obj, uint16_t instId, uint8_t acked, int32_t timeoutMs)
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{
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if (acked == 1) {
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return objectTransaction(obj, instId, TYPE_OBJ_ACK, timeoutMs);
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} else {
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return objectTransaction(obj, instId, TYPE_OBJ, timeoutMs);
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}
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}
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/**
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* Execute the requested transaction on an object.
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* \param[in] obj Object
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* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
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* \param[in] type Transaction type
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* TYPE_OBJ: send object,
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* TYPE_OBJ_REQ: request object update
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* TYPE_OBJ_ACK: send object with an ack
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* \return 0 Success
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* \return -1 Failure
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*/
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int32_t objectTransaction(UAVObjHandle obj, uint16_t instId, uint8_t type, int32_t timeoutMs)
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{
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int32_t respReceived;
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// Lock
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xSemaphoreTakeRecursive(lock, portMAX_DELAY);
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// Send object depending on if a response is needed
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if (type == TYPE_OBJ_ACK || type == TYPE_OBJ_REQ)
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{
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sendObject(obj, instId, type);
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respObj = obj;
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respInstId = instId;
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xSemaphoreGiveRecursive(lock); // need to release lock since the next call will block until a response is received
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xSemaphoreTake(respSema, 0); // the semaphore needs to block on the next call, here we make sure the value is zero (binary sema)
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respReceived = xSemaphoreTake(respSema, timeoutMs/portTICK_RATE_MS); // lock on object until a response is received (or timeout)
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// Check if a response was received
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if (respReceived == pdFALSE)
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{
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return -1;
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}
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else
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{
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return 0;
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}
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}
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else if (type == TYPE_OBJ)
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{
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sendObject(obj, instId, TYPE_OBJ);
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xSemaphoreGiveRecursive(lock);
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return 0;
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}
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else
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{
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xSemaphoreGiveRecursive(lock);
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return -1;
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}
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}
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/**
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* Process an byte from the telemetry stream.
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* \param[in] rxbyte Received byte
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* \return 0 Success
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* \return -1 Failure
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*/
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int32_t UAVTalkProcessInputStream(uint8_t rxbyte)
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{
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static uint8_t tmpBuffer[4];
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static UAVObjHandle obj;
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static uint8_t type;
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static uint32_t objId;
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static uint16_t instId;
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static uint32_t length;
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static uint16_t cs, csRx;
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static int32_t rxCount;
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static RxState state = STATE_SYNC;
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// Receive state machine
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switch (state) {
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case STATE_SYNC:
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if ((rxbyte & TYPE_MASK) == TYPE_VER )
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{
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cs = rxbyte;
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type = rxbyte;
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state = STATE_OBJID;
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rxCount = 0;
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}
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break;
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case STATE_OBJID:
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tmpBuffer[rxCount++] = rxbyte;
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if (rxCount == 4)
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{
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// Search for object, if not found reset state machine
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objId = (tmpBuffer[3] << 24) | (tmpBuffer[2] << 16) | (tmpBuffer[1] << 8) | (tmpBuffer[0]);
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obj = UAVObjGetByID(objId);
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if (obj == 0)
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{
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state = STATE_SYNC;
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}
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else
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{
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// Update checksum
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cs = updateChecksum(cs, tmpBuffer, 4);
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// Determine data length
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if (type == TYPE_OBJ_REQ || type == TYPE_ACK)
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{
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length = 0;
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}
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else
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{
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length = UAVObjGetNumBytes(obj);
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}
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// Check length and determine next state
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if (length >= MAX_PAYLOAD_LENGTH)
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{
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state = STATE_SYNC;
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}
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else
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{
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// Check if this is a single instance object (i.e. if the instance ID field is coming next)
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if ( UAVObjIsSingleInstance(obj) )
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{
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// If there is a payload get it, otherwise receive checksum
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if (length > 0)
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{
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state = STATE_DATA;
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}
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else
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{
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state = STATE_CS;
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}
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instId = 0;
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rxCount = 0;
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}
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else
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{
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state = STATE_INSTID;
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rxCount = 0;
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}
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}
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}
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}
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break;
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case STATE_INSTID:
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tmpBuffer[rxCount++] = rxbyte;
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if (rxCount == 2)
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{
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instId = (tmpBuffer[1] << 8) | (tmpBuffer[0]);
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cs = updateChecksum(cs, tmpBuffer, 2);
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rxCount = 0;
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// If there is a payload get it, otherwise receive checksum
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if (length > 0)
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{
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state = STATE_DATA;
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}
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else
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{
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state = STATE_CS;
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}
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}
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break;
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case STATE_DATA:
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rxBuffer[rxCount++] = rxbyte;
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if (rxCount == length)
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{
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cs = updateChecksum(cs, rxBuffer, length);
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state = STATE_CS;
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rxCount = 0;
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}
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break;
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case STATE_CS:
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tmpBuffer[rxCount++] = rxbyte;
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if (rxCount == 2)
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{
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csRx = (tmpBuffer[1] << 8) | (tmpBuffer[0]);
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if (csRx == cs)
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{
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xSemaphoreTakeRecursive(lock, portMAX_DELAY);
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receiveObject(type, obj, instId, rxBuffer, length);
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xSemaphoreGiveRecursive(lock);
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}
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state = STATE_SYNC;
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}
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break;
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default:
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state = STATE_SYNC;
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}
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// Done
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return 0;
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}
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/**
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* Receive an object. This function process objects received through the telemetry stream.
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* \param[in] type Type of received message (TYPE_OBJ, TYPE_OBJ_REQ, TYPE_OBJ_ACK, TYPE_ACK)
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* \param[in] obj Handle of the received object
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* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
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* \param[in] data Data buffer
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* \param[in] length Buffer length
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* \return 0 Success
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* \return -1 Failure
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*/
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int32_t receiveObject(uint8_t type, UAVObjHandle obj, uint16_t instId, uint8_t* data, int32_t length)
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{
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// Unpack object if the message is of type OBJ or OBJ_ACK
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if (type == TYPE_OBJ || type == TYPE_OBJ_ACK)
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{
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UAVObjUnpack(obj, instId, data);
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}
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// Send requested object if message is of type OBJ_REQ
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if (type == TYPE_OBJ_REQ)
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{
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sendObject(obj, instId, TYPE_OBJ);
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}
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// Send ACK if message is of type OBJ_ACK
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if (type == TYPE_OBJ_ACK)
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{
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sendObject(obj, instId, TYPE_ACK);
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}
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// If a response was pending on the object, unblock any waiting tasks
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if (type == TYPE_ACK || type == TYPE_OBJ)
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{
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if (respObj == obj && (respInstId = instId || respInstId == UAVOBJ_ALL_INSTANCES))
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{
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xSemaphoreGive(respSema);
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}
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}
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// Done
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return 0;
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}
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/**
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* Send an object through the telemetry link.
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* \param[in] obj Object handle to send
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* \param[in] instId The instance ID or UAVOBJ_ALL_INSTANCES for all instances
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* \param[in] type Transaction type
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* \return 0 Success
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* \return -1 Failure
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*/
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int32_t sendObject(UAVObjHandle obj, uint16_t instId, uint8_t type)
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{
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uint32_t numInst;
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uint32_t n;
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// Check if this operation is for a single instance or all
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if (instId == UAVOBJ_ALL_INSTANCES && !UAVObjIsSingleInstance(obj))
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{
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if (type == TYPE_OBJ || type == TYPE_OBJ_ACK)
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{
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// Get number of instances
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numInst = UAVObjGetNumInstances(obj);
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// Send all instances
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for (n = 0; n < numInst; ++n)
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{
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sendSingleObject(obj, n, type);
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}
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return 0;
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}
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else
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{
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return -1;
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}
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}
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else
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{
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return sendSingleObject(obj, instId, type);
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}
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}
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/**
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* Send an object through the telemetry link.
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* \param[in] obj Object handle to send
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* \param[in] instId The instance ID (can NOT be UAVOBJ_ALL_INSTANCES, use sendObject() instead)
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* \param[in] type Transaction type
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* \return 0 Success
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* \return -1 Failure
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*/
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int32_t sendSingleObject(UAVObjHandle obj, uint16_t instId, uint8_t type)
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{
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int32_t length;
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int32_t dataOffset;
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uint16_t cs = 0;
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uint32_t objId;
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// Check for valid packet type
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if (type != TYPE_OBJ && type != TYPE_OBJ_ACK && type != TYPE_OBJ_REQ && type != TYPE_ACK)
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{
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return -1;
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}
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// Setup type and object id fields
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objId = UAVObjGetID(obj);
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txBuffer[0] = type;
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txBuffer[1] = (uint8_t)(objId & 0xFF);
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txBuffer[2] = (uint8_t)((objId >> 8) & 0xFF);
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txBuffer[3] = (uint8_t)((objId >> 16) & 0xFF);
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txBuffer[4] = (uint8_t)((objId >> 24) & 0xFF);
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// Setup instance ID if one is required
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if (UAVObjIsSingleInstance(obj))
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{
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dataOffset = 5;
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}
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else
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{
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txBuffer[5] = (uint8_t)(instId & 0xFF);
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txBuffer[6] = (uint8_t)((instId >> 8) & 0xFF);
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dataOffset = 7;
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}
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// Determine data length
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if (type == TYPE_OBJ_REQ || type == TYPE_ACK)
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{
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length = 0;
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}
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else
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{
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length = UAVObjGetNumBytes(obj);
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}
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// Check length
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if (length >= MAX_PAYLOAD_LENGTH)
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{
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return -1;
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}
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// Copy data (if any)
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if (length > 0)
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{
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if ( UAVObjPack(obj, instId, &txBuffer[dataOffset]) < 0 )
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{
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return -1;
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}
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}
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// Calculate checksum
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cs = 0;
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cs = updateChecksum(cs, txBuffer, dataOffset+length);
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txBuffer[dataOffset+length] = (uint8_t)(cs & 0xFF);
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txBuffer[dataOffset+length+1] = (uint8_t)((cs >> 8) & 0xFF);
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// Send buffer
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if (outStream!=NULL) (*outStream)(txBuffer, dataOffset+length+CHECKSUM_LENGTH);
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// Done
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return 0;
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}
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/**
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* Update checksum.
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* TODO: Replace with CRC-16
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* \param[in] data Data buffer to update checksum on
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* \param[in] length Length of buffer
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* \return Updated checksum
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*/
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uint16_t updateChecksum(uint16_t cs, uint8_t* data, int32_t length)
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{
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int32_t n;
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for (n = 0; n < length; ++n)
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{
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cs += (uint16_t)data[n];
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}
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return cs;
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}
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