/**************************************************************************************************Filename: mac_rx.cRevised: $Date: 2007-10-08 14:05:36 -0700 (Mon, 08 Oct 2007) $Revision: $Revision: 15624 $Description: Describe the purpose and contents of the file.Copyright 2006-2009 Texas Instruments Incorporated. All rights reserved.IMPORTANT: Your use of this Software is limited to those specific rightsgranted under the terms of a software license agreement between the userwho downloaded the software, his/her employer (which must be your employer)and Texas Instruments Incorporated (the "License"). You may not use thisSoftware unless you agree to abide by the terms of the License. The Licenselimits your use, and you acknowledge, that the Software may not be modified,copied or distributed unless embedded on a Texas Instruments microcontrolleror used solely and exclusively in conjunction with a Texas Instruments radiofrequency transceiver, which is integrated into your product. Other than forthe foregoing purpose, you may not use, reproduce, copy, prepare derivativeworks of, modify, distribute, perform, display or sell this Software and/orits documentation for any purpose.YOU FURTHER ACKNOWLEDGE AND AGREE THAT THE SOFTWARE AND DOCUMENTATION AREPROVIDED 揂S IS?WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED,INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY, TITLE,NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALLTEXAS INSTRUMENTS OR ITS LICENSORS BE LIABLE OR OBLIGATED UNDER CONTRACT,NEGLIGENCE, STRICT LIABILITY, CONTRIBUTION, BREACH OF WARRANTY, OR OTHERLEGAL EQUITABLE THEORY ANY DIRECT OR INDIRECT DAMAGES OR EXPENSESINCLUDING BUT NOT LIMITED TO ANY INCIDENTAL, SPECIAL, INDIRECT, PUNITIVEOR CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA, COST OF PROCUREMENTOF SUBSTITUTE GOODS, TECHNOLOGY, SERVICES, OR ANY CLAIMS BY THIRD PARTIES(INCLUDING BUT NOT LIMITED TO ANY DEFENSE THEREOF), OR OTHER SIMILAR COSTS.Should you have any questions regarding your right to use this Software,contact Texas Instruments Incorporated at www.TI.com.
**************************************************************************************************//* ------------------------------------------------------------------------------------------------* Includes* ------------------------------------------------------------------------------------------------*//* hal */
#include "hal_defs.h"
#include "hal_types.h"/* high-level */
#include "mac_high_level.h"
#include "mac_spec.h"/* exported low-level */
#include "mac_low_level.h"/* low-level specific */
#include "mac_rx.h"
#include "mac_tx.h"
#include "mac_rx_onoff.h"
#include "mac_radio.h"/* target specific */
#include "mac_radio_defs.h"
#include "mac_autopend.h"/* debug */
#include "mac_assert.h"//add by gjh
#include "hal_uart.h"/* ------------------------------------------------------------------------------------------------* Defines* ------------------------------------------------------------------------------------------------*/
#define MAX_PAYLOAD_BYTES_READ_PER_INTERRUPT 16/* adjustable to tune performance *//* receive FIFO bytes needed to start a valid receive (see function rxStartIsr for details) */
#define RX_THRESHOLD_START_LEN (MAC_PHY_PHR_LEN + \MAC_FCF_FIELD_LEN + \MAC_SEQ_NUM_FIELD_LEN + \MAC_FCS_FIELD_LEN)/* maximum size of addressing fields (note: command frame identifier processed as part of address) */
#define MAX_ADDR_FIELDS_LEN ((MAC_EXT_ADDR_FIELD_LEN + MAC_PAN_ID_FIELD_LEN) * 2)/* addressing mode reserved value */
#define ADDR_MODE_RESERVERED 1/* length of command frame identifier */
#define CMD_FRAME_ID_LEN 1/* packet size mask is equal to the maximum value */
#define PHY_PACKET_SIZE_MASK 0x7F//最多127個字節/* value for promiscuous off, must not conflict with other mode variants from separate include files */
#define PROMISCUOUS_MODE_OFF 0x00/* bit of proprietary FCS format that indicates if the CRC is OK */
#define PROPRIETARY_FCS_CRC_OK_BIT 0x80//最高位為1/* dummy length value for unused entry in lookup table */
#define DUMMY_LEN 0xBE/* value for rxThresholdIntState */
#define RX_THRESHOLD_INT_STATE_INACTIVE 0
#define RX_THRESHOLD_INT_STATE_ACTIVE 1
#define RX_THRESHOLD_INT_STATE_RESET 2/* ------------------------------------------------------------------------------------------------* Macros* ------------------------------------------------------------------------------------------------*/
#define MEM_ALLOC(x) macDataRxMemAlloc(x)
#define MEM_FREE(x) macDataRxMemFree((uint8 **)x)/** Macro for encoding frame control information into internal flags format.* Parameter is pointer to the frame. NOTE! If either the internal frame* format *or* the specification changes, this macro will need to be modified.*/
#define INTERNAL_FCF_FLAGS(p) ((((p)[1] >> 4) & 0x03) | ((p)[0] & 0x78))/** The radio replaces the actual FCS with different information. This proprietary FCS is* the same length as the original and includes:* 1) the RSSI value* 2) the average correlation value (used for LQI)* 3) a CRC passed bit** These macros decode the proprietary FCS. The macro parameter is a pointer to the two byte FCS.*/
#define PROPRIETARY_FCS_RSSI(p) ((int8)((p)[0]))
#define PROPRIETARY_FCS_CRC_OK(p) ((p)[1] & PROPRIETARY_FCS_CRC_OK_BIT) //取最高位
#define PROPRIETARY_FCS_CORRELATION_VALUE(p) ((p)[1] & ~PROPRIETARY_FCS_CRC_OK_BIT) //取低7位/* ------------------------------------------------------------------------------------------------* Global Variables* ------------------------------------------------------------------------------------------------*/
uint8 macRxActive;
uint8 macRxFilter;
uint8 macRxOutgoingAckFlag; //此變量用于存儲幀控制域中的ACK請求位/* ------------------------------------------------------------------------------------------------* Local Constants* ------------------------------------------------------------------------------------------------*/staticconst uint8 CODE macRxAddrLen[] = //用于匹配究竟MAC幀用的是何種地址模式，源、目的地址模式總共有4種
{0, /* no address *///不存在PAN標識符子域和地址子域DUMMY_LEN, /* reserved *///保留的MAC_PAN_ID_FIELD_LEN + MAC_SHORT_ADDR_FIELD_LEN, /* short address + pan id *///16位短地址MAC_PAN_ID_FIELD_LEN + MAC_EXT_ADDR_FIELD_LEN /* extended address + pan id *///64位擴展地址
};/* ------------------------------------------------------------------------------------------------* Local Prototypes* ------------------------------------------------------------------------------------------------*/staticvoid rxHaltCleanupFinalStep(void);staticvoid rxStartIsr(void); //剛收到packet的中斷服務程序， 第1個執行staticvoid rxAddrIsr(void); //處理地址的中斷服務程序， 第2個執行staticvoid rxPayloadIsr(void); //payload數據接收的中斷服務程序， 第3個執行staticvoid rxDiscardIsr(void); //處理丟棄packet的中斷服務程序， staticvoid rxFcsIsr(void); //處理FCS的中斷服務程序，staticvoid rxPrepPayload(void);
staticvoid rxDiscardFrame(void);
staticvoid rxDone(void); //packet接收完的中斷服務程序， 第 個執行staticvoid rxPostRxUpdates(void); //packet接收完后需更新的中斷服務程序， 最后執行/* ------------------------------------------------------------------------------------------------* Local Variables* ------------------------------------------------------------------------------------------------*/staticvoid (* pFuncRxState)(void);
static macRx_t * pRxBuf; //存儲數據的structstatic uint8 rxBuf[MAC_PHY_PHR_LEN + MAC_FCF_FIELD_LEN + MAC_SEQ_NUM_FIELD_LEN]; // 物理幀頭 1字節 + 幀控制域 2字節 + 序列號 1字節 = 4字節static uint8 rxUnreadLen;
static uint8 rxNextLen;
static uint8 rxPayloadLen;
static uint8 rxFilter;
static uint8 rxPromiscuousMode;
static uint8 rxIsrActiveFlag;
static uint8 rxResetFlag;
static uint8 rxFifoOverflowCount;/*************************************************************************************************** @fn macRxInit** @brief Initialize receive variable states.** @param none** @return none***************************************************************************************************/
MAC_INTERNAL_API void macRxInit(void)
{macRxFilter = RX_FILTER_OFF;rxPromiscuousMode = PROMISCUOUS_MODE_OFF; //原先是關閉混雜模式：PROMISCUOUS_MODE_OFF，被我改為：MAC_PROMISCUOUS_MODE_WITH_BAD_CRCpRxBuf = NULL; /* required for macRxReset() to function correctly */macRxActive = MAC_RX_ACTIVE_NO_ACTIVITY;pFuncRxState = &rxStartIsr; //函數指針pFuncRxState指向rxStartIsrmacRxOutgoingAckFlag = 0;rxIsrActiveFlag = 0;rxResetFlag = 0;rxFifoOverflowCount = 0;
}/*************************************************************************************************** @fn macRxRadioPowerUpInit //上電后RX的初始化** @brief Initialization for after radio first powers up.** @param none** @return none***************************************************************************************************/
MAC_INTERNAL_API void macRxRadioPowerUpInit(void)
{/* set threshold at initial value */MAC_RADIO_SET_RX_THRESHOLD(RX_THRESHOLD_START_LEN); //RX_THRESHOLD_START_LEN = MAC_PHY_PHR_LEN + MAC_FCF_FIELD_LEN + MAC_SEQ_NUM_FIELD_LEN + MAC_FCS_FIELD_LEN =1+2+1+2=6字節/* clear any accidental threshold interrupt that happened as part of power up sequence */MAC_RADIO_CLEAR_RX_THRESHOLD_INTERRUPT_FLAG();/* enable threshold interrupts */MAC_RADIO_ENABLE_RX_THRESHOLD_INTERRUPT();
}/*************************************************************************************************** @fn macRxTxReset** @brief Reset the receive state.** @param none** @return none***************************************************************************************************/
MAC_INTERNAL_API void macRxTxReset(void)
{/* forces receiver off, cleans up by calling macRxHaltCleanup() and macTxHaltCleanup() */macRxHardDisable();/** Note : transmit does not require any reset logic* beyond what macRxHardDisable() provides.*//* restore deault filter mode to off */macRxFilter = RX_FILTER_OFF;/* return promiscuous mode to default off state */macRxPromiscuousMode(MAC_PROMISCUOUS_MODE_OFF); //關閉混雜模式
}/*************************************************************************************************** @fn macRxHaltCleanup** @brief Cleanup up the receive logic after receiver is forced off.** @param none** @return none***************************************************************************************************/
MAC_INTERNAL_API void macRxHaltCleanup(void)
{rxResetFlag = 1;if (!rxIsrActiveFlag){rxHaltCleanupFinalStep();rxResetFlag = 0;}
}/*=================================================================================================* @fn rxHaltCleanupFinalStep** @brief Required cleanup if receiver is halted in the middle of a receive.** @param none** @return none*=================================================================================================*/staticvoid rxHaltCleanupFinalStep(void)
{/* cancel any upcoming ACK transmit complete callback */MAC_RADIO_CANCEL_ACK_TX_DONE_CALLBACK();/* set start of frame threshold */MAC_RADIO_SET_RX_THRESHOLD(RX_THRESHOLD_START_LEN); //重新設置成6字節/* flush the receive FIFO */MAC_RADIO_FLUSH_RX_FIFO();/* clear any receive interrupt that happened to squeak through */MAC_RADIO_CLEAR_RX_THRESHOLD_INTERRUPT_FLAG();/* if data buffer has been allocated, free it *///如果分配了數據buffer，就釋放它if (pRxBuf != NULL){MEM_FREE((uint8 **)&pRxBuf);}pRxBuf = NULL; /* needed to indicate buffer is no longer allocated */pFuncRxState = &rxStartIsr; //函數指針pFuncRxState指向rxStartIsr/* if receive was active, perform the post receive updates */if (macRxActive || macRxOutgoingAckFlag){macRxActive = MAC_RX_ACTIVE_NO_ACTIVITY;macRxOutgoingAckFlag = 0; //0 為不需要應答rxPostRxUpdates();}
}/*************************************************************************************************** @fn macRxThresholdIsr** @brief Interrupt service routine called when bytes in FIFO reach threshold value. //重要！當FIFO中字節數達到閾值時，執行的中斷服務程序* It implements a state machine for receiving a packet. //讀取packet的任何一個部分，都需要通過這個中斷服務程序執行** @param none** @return none***************************************************************************************************/
MAC_INTERNAL_API void macRxThresholdIsr(void)
{/* if currently reseting, do not execute receive ISR logic */if (rxResetFlag){return;}/** Call the function that handles the current receive state.* A flag is set for the duration of the call to indicate* the ISR is executing. This is necessary for the reset* logic so it does not perform a reset in the middle of* executing the ISR.*/rxIsrActiveFlag = 1; //正在執行中斷服務程序的標志位(*pFuncRxState)(); //執行當前該執行的中斷服務程序，pFuncRxState的函數指針時刻在變rxIsrActiveFlag = 0;/* if a reset occurred during the ISR, peform cleanup here */if (rxResetFlag){rxHaltCleanupFinalStep();rxResetFlag = 0;}
}/*=================================================================================================* @fn rxStartIsr** @brief First ISR state for receiving a packet - compute packet length, allocate //第一步要執行的服務中斷程序，包括計算包長度、分配buffer、初始化buffer* buffer, initialize buffer. Acknowledgements are handled immediately without //如果是ACK，則先處理，不用分配buffer* allocating a buffer.** @param none** @return none*=================================================================================================*/staticvoid rxStartIsr(void)
{uint8 addrLen; //記錄地址長度的變量uint8 ackWithPending;uint8 dstAddrMode; //目的地址模式uint8 srcAddrMode; //源地址模式MAC_ASSERT(!macRxActive); /* receive on top of receive *//* indicate rx is active */macRxActive = MAC_RX_ACTIVE_STARTED; /** For bullet proof functionality, need to see if the receiver was just turned off.* The logic to request turning off the receiver, disables interrupts and then checks* the value of macRxActive. If it is TRUE, the receiver will not be turned off.** There is a small hole though. It's possible to attempt turning off the receiver* in the window from when the receive interrupt fires and the point where macRxActive* is set to TRUE. To plug this hole, the on/off status must be tested *after** macRxActive has been set. If the receiver is off at this point, there is nothing* in the RX fifo and the receive is simply aborted.** Also, there are some considerations in case a hard disable just happened. Usually,* the receiver will just be off at this point after a hard disable. The check described* above will account for this case too. However, if a hard disable were immediately* followed by an enable, the receiver would be on. To catch this case, the receive* FIFO is also tested to see if it is empty. Recovery is identical to the other cases.*/if (!macRxOnFlag || MAC_RADIO_RX_FIFO_IS_EMPTY()){/* reset active flag */macRxActive = MAC_RX_ACTIVE_NO_ACTIVITY;/** To be absolutely bulletproof, must make sure no transmit queue'ed up during* the tiny, tiny window when macRxActive was not zero.*/rxPostRxUpdates();/* return immediately from here */return;}/** If interrupts are held off for too long it's possible the previous "transmit done"* callback is pending. If this is the case, it needs to be completed before* continuing with the receive logic.*/MAC_RADIO_FORCE_TX_DONE_IF_PENDING();/** It's possible receive logic is still waiting for confirmation of an ACK that went out* for the previous receive. This is OK but the callback needs to be canceled at this point.* That callback execute receive cleanup logic that will run at the completion* of *this* receive. Also, it is important the flag for the outgoing ACK to be cleared.*/MAC_RADIO_CANCEL_ACK_TX_DONE_CALLBACK();macRxOutgoingAckFlag = 0;/** Make a module-local copy of macRxFilter. This prevents the selected* filter from changing in the middle of a receive.*/rxFilter = macRxFilter;/*-------------------------------------------------------------------------------* Read initial frame information from FIFO.** This code is not triggered until the following are in the RX FIFO:* frame length - one byte containing length of MAC frame (excludes this field)* frame control field - two bytes defining frame type, addressing fields, control flags* sequence number - one byte unique sequence identifier* additional two bytes - these bytes are available in case the received frame is an ACK,* if so, the frame can be verified and responded to immediately,* if not an ACK, these bytes will be processed normally*///其實就是一個ACK的長度5字節 + 物理幀頭1字節 =6字節/* read frame length, frame control field, and sequence number from FIFO */MAC_RADIO_READ_RX_FIFO(rxBuf, MAC_PHY_PHR_LEN + MAC_FCF_FIELD_LEN + MAC_SEQ_NUM_FIELD_LEN); //讀取5個字節到rxBuf/* bytes to read from FIFO equals frame length minus length of MHR fields just read from FIFO */rxUnreadLen = (rxBuf[0] & PHY_PACKET_SIZE_MASK) - MAC_FCF_FIELD_LEN - MAC_SEQ_NUM_FIELD_LEN; //還未讀取的字節數=物理幀頭值（幀長度）- 2字節幀控制域 -1字節序列號/** Workaround for chip bug #1547. The receive buffer can sometimes be corrupted by hardware.* This usually occurs under heavy traffic. If a corrupted receive buffer is detected* the entire receive buffer is flushed.** In the case that this workaround is not needed, an assert is used to make sure the* receive length field is not corrupted. This is important because a corrupted receive* length field is utterly fatal and, if not caught here, extremely hard to track down.*/if (macChipVersion == REV_A){if ((rxUnreadLen > (MAC_A_MAX_PHY_PACKET_SIZE - MAC_FCF_FIELD_LEN - MAC_SEQ_NUM_FIELD_LEN)) || //如果rxUnreadLen更大，說明PHY的物理幀頭出錯，保留位為1，導致PSDU的長度大于127字節，出錯了(MAC_FRAME_TYPE(&rxBuf[1]) > MAC_FRAME_TYPE_MAX_VALID)) // MAC_FRAME_TYPE(&rxBuf[1]):取幀控制域的前3bit（幀類型），如果大于3，則出錯，沒有此類幀{MAC_RADIO_FLUSH_RX_FIFO(); // the entire receive buffer is flushed.rxDone();return;}}else{/* radio supplied a corrupted receive buffer length */MAC_ASSERT(rxUnreadLen <= (MAC_A_MAX_PHY_PACKET_SIZE - MAC_FCF_FIELD_LEN - MAC_SEQ_NUM_FIELD_LEN)); //閃燈以示錯誤}/*-------------------------------------------------------------------------------* Process ACKs.** If this frame is an ACK, process it immediately and exit from here. //如果是一個ACK幀，則立即處理，并從此處完成接收* If this frame is not an ACK and transmit is listening for an ACK, let //如果不是ACK，而發送狀態正在等待一個ACK，則讓transmit logic知道收到了一個非ACK幀，結束transmit logic* the transmit logic know an non-ACK was received so transmit can complete.** In promiscuous mode ACKs are treated like any other frame. //在混雜模式下，ACK幀與其它幀被同等對待*/if ((MAC_FRAME_TYPE(&rxBuf[1]) == MAC_FRAME_TYPE_ACK) && (rxPromiscuousMode == PROMISCUOUS_MODE_OFF)) //識別出是應答幀，且不是在混雜模式{halIntState_t s;uint8 fcsBuf[MAC_FCF_FIELD_LEN]; //定義2個字節的buf存儲ACK幀的FCS校驗碼（其實并非原來的FCS校驗碼，而是包含了RSSI值與是否校驗正確的2個byte，具體看PROPRIETARY_FCS_RSSI的定義）/** There are guaranteed to be two unread bytes in the FIFO. By defintion, for ACK frames //FIFO中至少還有2個字節的數據未讀* these two bytes will be the FCS. //如果是ACK幀，則是FCS校驗位*//* read FCS from FIFO (threshold set so bytes are guaranteed to be there) */MAC_RADIO_READ_RX_FIFO(fcsBuf, MAC_FCS_FIELD_LEN); //讀取SFR中RFD的兩個字節，即為ACK幀的FCS校驗碼/** This critical section ensures that the ACK timeout won't be triggered in the* millde of receiving the ACK frame.*/HAL_ENTER_CRITICAL_SECTION(s);/* see if transmit is listening for an ACK *///看看是不是發射端在等待一個ACKif (macTxActive == MAC_TX_ACTIVE_LISTEN_FOR_ACK){MAC_ASSERT(pMacDataTx != NULL); /* transmit buffer must be present *//* record link quality metrics for the receive ACK *///記錄RSSI值和correlation{int8 rssiDbm;uint8 corr;rssiDbm = PROPRIETARY_FCS_RSSI(fcsBuf) + MAC_RADIO_RSSI_OFFSET; //獲取RSSI，原來在fcsBuf的第一個字節中MAC_RADIO_RSSI_LNA_OFFSET(rssiDbm);corr = PROPRIETARY_FCS_CORRELATION_VALUE(fcsBuf); //(fcsBuf)[1] & 0x7F, 存儲在fcsBuf的第二個字節的低7位pMacDataTx->internal.mpduLinkQuality = macRadioComputeLQI(rssiDbm, corr); //其實并沒有用corr來計算LQI，只用了RSSI，計算ED，即作為LQIpMacDataTx->internal.correlation = corr; //pMacDataTx->internal.rssi= rssiDbm;}/** It's okay if the ACK timeout is triggered here. The callbacks for ACK received* or ACK not received will check "macTxActive" flag before taking any actions.*/HAL_EXIT_CRITICAL_SECTION(s);/** An ACK was received so transmit logic needs to know. If the FCS failed,* the transmit logic still needs to know. In that case, treat the frame* as a non-ACK to complete the active transmit.*/if (PROPRIETARY_FCS_CRC_OK(fcsBuf)) //檢驗fcsBuf的第二個字節的最高位是否為1，如果是1，則FCS檢驗成功，如果是0，則校驗失敗{/* call transmit logic to indicate ACK was received */macTxAckReceivedCallback(MAC_SEQ_NUMBER(&rxBuf[1]), MAC_FRAME_PENDING(&rxBuf[1])); //記錄序列號}else//FCS檢驗錯誤{macTxAckNotReceivedCallback();}}else{HAL_EXIT_CRITICAL_SECTION(s);}/* receive is done, exit from here *///接收完畢rxDone();return;}elseif (macTxActive == MAC_TX_ACTIVE_LISTEN_FOR_ACK) //ACK超時,或其他問題{macTxAckNotReceivedCallback(); }/*-------------------------------------------------------------------------------* Apply filtering.** For efficiency, see if filtering is even 'on' before processing. Also test* to make sure promiscuous mode is disabled. If promiscuous mode is enabled,* do not apply filtering.*/if ((rxFilter != RX_FILTER_OFF) && !rxPromiscuousMode){if (/* filter all frames */(rxFilter == RX_FILTER_ALL) ||/* filter non-beacon frames */((rxFilter == RX_FILTER_NON_BEACON_FRAMES) &&(MAC_FRAME_TYPE(&rxBuf[1]) != MAC_FRAME_TYPE_BEACON)) ||/* filter non-command frames */((rxFilter == RX_FILTER_NON_COMMAND_FRAMES) &&((MAC_FRAME_TYPE(&rxBuf[1]) != MAC_FRAME_TYPE_COMMAND)))){/* discard rest of frame */rxDiscardFrame();return;}}/*-------------------------------------------------------------------------------* Compute length of addressing fields. Compute payload length.*//* decode addressing modes */dstAddrMode = MAC_DEST_ADDR_MODE(&rxBuf[1]); //取目的地址模式，在幀控制域中，Bit:10~11srcAddrMode = MAC_SRC_ADDR_MODE(&rxBuf[1]); //取源地址模式，在幀控制域中，Bit:14~15/** Workaround for chip bug #1547. The receive buffer can sometimes be corrupted by hardware.* This usually occurs under heavy traffic. If a corrupted receive buffer is detected* the entire receive buffer is flushed.*/if (macChipVersion == REV_A){if ((srcAddrMode == ADDR_MODE_RESERVERED) || (dstAddrMode == ADDR_MODE_RESERVERED)) //當源地址模式或目的地址模式的兩個bit是01這一保留值時，認為出錯了{MAC_RADIO_FLUSH_RX_FIFO();rxDone();return;}}/** Compute the addressing field length. A lookup table based on addressing* mode is used for efficiency. If the source address is present and the* frame is intra-PAN, the PAN Id is not repeated. In this case, the address* length is adjusted to match the smaller length.*/addrLen = macRxAddrLen[dstAddrMode] + macRxAddrLen[srcAddrMode]; //計算MHR中地址域的總字節數（包括4項：目的PAN標識符 + 目的地址域 + 源PAN標識符 + 源地址域 ）if ((srcAddrMode != SADDR_MODE_NONE) && MAC_INTRA_PAN(&rxBuf[1])) //判斷是否內部PAN，標志位在幀控制域的Bit:6{addrLen -= MAC_PAN_ID_FIELD_LEN; //如果是，則減去PAN ID所占的2個字節}/** If there are not enough unread bytes to include the computed address* plus FCS field, the frame is corrupted and must be discarded.*/if ((addrLen + MAC_FCS_FIELD_LEN) > rxUnreadLen) //如果出現地址域字節數 + 2字節的FCS > 未讀的字節數 ，則收到的包出錯了{/* discard frame and exit */rxDiscardFrame();return;}/* payload length is equal to unread bytes minus address length, minus the FCS */rxPayloadLen = rxUnreadLen - addrLen - MAC_FCS_FIELD_LEN; //payload的字節數=待讀字節數-地址域字節數-2字節的FCS/*-------------------------------------------------------------------------------* Allocate memory for the incoming frame.*/pRxBuf = (macRx_t *) MEM_ALLOC(sizeof(macRx_t) + rxPayloadLen);if (pRxBuf == NULL) //buffer分配失敗{/* Cancel the outgoing TX ACK */MAC_RADIO_CANCEL_TX_ACK();/* buffer allocation failed, discard the frame and exit*/rxDiscardFrame();return;}/*-------------------------------------------------------------------------------* Set up to process ACK request. Do not ACK if in promiscuous mode.*/ackWithPending = 0;if (!rxPromiscuousMode) //如果是非混雜模式{macRxOutgoingAckFlag = MAC_ACK_REQUEST(&rxBuf[1]); //將幀控制域中的ACK請求位賦值給macRxOutgoingAckFlag}/*-------------------------------------------------------------------------------* Process any ACK request.*/if (macRxOutgoingAckFlag) //如果需要接收方返回應答{halIntState_t s;/** This critical section ensures that the callback ISR is initiated within time* to guarantee correlation with the strobe.*/HAL_ENTER_CRITICAL_SECTION(s);/* Do not ack data packet with pending more data */if( MAC_FRAME_TYPE(&rxBuf[1]) == MAC_FRAME_TYPE_COMMAND ) //如果是命令幀{if( macRxCheckMACPendingCallback()) //被封裝的函數，看不到{/* Check is any mac data pending for end devices */ackWithPending = MAC_RX_FLAG_ACK_PENDING;}else{if( macSrcMatchIsEnabled ){/* When autopend is enabled, check if allpending is set to true */if( MAC_SrcMatchCheckAllPending() == MAC_AUTOACK_PENDING_ALL_ON ){ackWithPending = MAC_RX_FLAG_ACK_PENDING;}}else{/* When autopend is disabled, check the application pending callback */if( macRxCheckPendingCallback() ){ackWithPending = MAC_RX_FLAG_ACK_PENDING;}}}}if( ackWithPending == MAC_RX_FLAG_ACK_PENDING ){MAC_RADIO_TX_ACK_PEND();}else{MAC_RADIO_TX_ACK();}/* request a callback to macRxAckTxDoneCallback() when the ACK transmit has finished */MAC_RADIO_REQUEST_ACK_TX_DONE_CALLBACK();HAL_EXIT_CRITICAL_SECTION(s);}/*-------------------------------------------------------------------------------* Populate the receive buffer going up to high-level. 將收到的數據向上層傳遞*//* configure the payload buffer */pRxBuf->msdu.p = (uint8 *) (pRxBuf + 1); //payload的指針pRxBuf->msdu.len = rxPayloadLen; //payload的長度/* set internal values */pRxBuf->mac.srcAddr.addrMode = srcAddrMode; //記錄源地址模式pRxBuf->mac.dstAddr.addrMode = dstAddrMode; //記錄目的地址模式pRxBuf->mac.timestamp = MAC_RADIO_BACKOFF_CAPTURE();pRxBuf->mac.timestamp2 = MAC_RADIO_TIMER_CAPTURE();pRxBuf->internal.frameType = MAC_FRAME_TYPE(&rxBuf[1]); //記錄MAC幀類型pRxBuf->mac.dsn = MAC_SEQ_NUMBER(&rxBuf[1]); //記錄幀序列號pRxBuf->internal.flags = INTERNAL_FCF_FLAGS(&rxBuf[1]) | ackWithPending;pRxBuf->sec.securityLevel = MAC_SEC_LEVEL_NONE;/*-------------------------------------------------------------------------------* If the processing the addressing fields does not require more bytes from* the FIFO go directly address processing function. Otherwise, configure* interrupt to jump there once bytes are received.*/if (addrLen == 0) //地址域長度為0byte{/* no addressing fields to read, prepare for payload interrupts */pFuncRxState = &rxPayloadIsr; //pFuncRxState函數指針指向處理payload的中斷服務程序rxPrepPayload(); //不用處理地址，直接準備接收處理payload}else{/* need to read and process addressing fields, prepare for address interrupt */rxNextLen = addrLen; // rxNextLen等于地址域長度MAC_RADIO_SET_RX_THRESHOLD(rxNextLen); //需要處理地址域的數據，接收地址域pFuncRxState = &rxAddrIsr; //pFuncRxState函數指針指向處理地址的中斷服務程序rxAddrIsr}
}/*=================================================================================================* @fn rxAddrIsr //處理地址的中斷服務程序** @brief Receive ISR state for decoding address. Reads and stores the address information* from the incoming packet.** @param none** @return none*=================================================================================================*/staticvoid rxAddrIsr(void)
{uint8 buf[MAX_ADDR_FIELDS_LEN]; //分配bufferuint8 dstAddrMode;uint8 srcAddrMode;uint8 * p;MAC_ASSERT(rxNextLen != 0); /* logic assumes at least one address byte in buffer *//* read out address fields into local buffer in one shot */MAC_RADIO_READ_RX_FIFO(buf, rxNextLen); //讀取地址域到buf/* set pointer to buffer with addressing fields */p = buf; //將指針p指向buf/* destination address */dstAddrMode = MAC_DEST_ADDR_MODE(&rxBuf[1]); //目的地址模式if (dstAddrMode != SADDR_MODE_NONE) {pRxBuf->mac.srcPanId = pRxBuf->mac.dstPanId = BUILD_UINT16(p[0], p[1]); //讀取PAN idp += MAC_PAN_ID_FIELD_LEN; //指針p前移2字節，buf數字前移2字節，將指向目的地址所在字節if (dstAddrMode == SADDR_MODE_EXT) //目的地址包含64位擴展地址{sAddrExtCpy(pRxBuf->mac.dstAddr.addr.extAddr, p); //將目的地址（擴展）復制到pRxBuf->mac.dstAddr.addr.extAddr中p += MAC_EXT_ADDR_FIELD_LEN; //指針p前移8字節，buf數字前移2字節，將指向源地址所在字節}else//目的地址包含16位短地址{pRxBuf->mac.dstAddr.addr.shortAddr = BUILD_UINT16(p[0], p[1]); //將目的地址（短）復制到pRxBuf->mac.dstAddr.addr.shortAddr中p += MAC_SHORT_ADDR_FIELD_LEN; //指針p前移2字節，buf數字前移2字節，將指向源地址所在字節}}/* sources address */srcAddrMode = MAC_SRC_ADDR_MODE(&rxBuf[1]); //源地址模式if (srcAddrMode != SADDR_MODE_NONE){if (!(pRxBuf->internal.flags & MAC_RX_FLAG_INTRA_PAN)){pRxBuf->mac.srcPanId = BUILD_UINT16(p[0], p[1]); //讀取源地址的PAN idp += MAC_PAN_ID_FIELD_LEN;}if (srcAddrMode == SADDR_MODE_EXT) //源地址包含64位擴展地址{sAddrExtCpy(pRxBuf->mac.srcAddr.addr.extAddr, p); //將源地址（擴展）復制到pRxBuf->mac.srcAddr.addr.extAddr中}else//源地址包含16位短地址{pRxBuf->mac.srcAddr.addr.shortAddr = BUILD_UINT16(p[0], p[1]); //將源地址（擴展）復制到pRxBuf->mac.srcAddr.addr.shortAddr中}}/*-------------------------------------------------------------------------------* Prepare for payload interrupts.*/pFuncRxState = &rxPayloadIsr; //pFuncRxState函數指針指向處理接收數據的中斷服務程序rxPayloadIsrrxPrepPayload(); //執行準備接收數據的函數
}/*=================================================================================================* @fn rxPrepPayload** @brief Common code to prepare for the payload ISR.** @param none** @return none*=================================================================================================*/staticvoid rxPrepPayload(void)
{if (rxPayloadLen == 0) //如果rxPayloadLen=0，即無payload{MAC_RADIO_SET_RX_THRESHOLD(MAC_FCS_FIELD_LEN); //準備FCS校驗pFuncRxState = &rxFcsIsr; //pFuncRxState函數指針指向處理FCS的中斷服務程序rxFcsIsr}else{rxNextLen = MIN(rxPayloadLen, MAX_PAYLOAD_BYTES_READ_PER_INTERRUPT); //每次最多讀取16個字節的數據，（16這個值可調）MAC_RADIO_SET_RX_THRESHOLD(rxNextLen); //接收rxNextLen個字節的數據}
}/*=================================================================================================* @fn rxPayloadIsr** @brief Receive ISR state for reading out and storing the packet payload.** @param none** @return none*=================================================================================================*/staticvoid rxPayloadIsr(void)
{MAC_RADIO_READ_RX_FIFO(pRxBuf->msdu.p, rxNextLen); //將rxNextLen個數據讀取到pRxBuf->msdu.p中//add by jionghong 我自己加的，為了輸出讀取到的payloadhalIntState_t intState;// Hold off interruptsHAL_ENTER_CRITICAL_SECTION(intState);// HalUARTWrite(0, &rxNextLen , 1);HalUARTWrite(0, pRxBuf->msdu.p , rxNextLen);// HalUARTWrite(0, "\n", 1); //回車換行// Release interruptsHAL_EXIT_CRITICAL_SECTION(intState);pRxBuf->msdu.p += rxNextLen; //指針指向的更新，隨著數據的接收，不斷向前rxPayloadLen -= rxNextLen; //更新待讀取的payload字節數rxPrepPayload(); //重新設置讀取payload的字節數
}/*=================================================================================================* @fn rxFcsIsr** @brief Receive ISR state for handling the FCS.** @param none** @return none*=================================================================================================*/staticvoid rxFcsIsr(void)
{uint8 crcOK; //用于記錄是否通過CRC校驗的變量uint8 ackWithPending = 0;/* read FCS, rxBuf is now available storage */MAC_RADIO_READ_RX_FIFO(rxBuf, MAC_FCS_FIELD_LEN); //讀取FCS的2個byte，（其實并非原來的FCS校驗碼，而是包含了RSSI值與是否校驗正確的2個byte，具體看PROPRIETARY_FCS_RSSI的定義）/** The FCS has actually been replaced within the radio by a proprietary version of the FCS.* This proprietary FCS is two bytes (same length as the real FCS) and contains:* 1) the RSSI value* 2) the average correlation value (used for LQI)* 3) a CRC passed bit*//* save the "CRC-is-OK" status */crcOK = PROPRIETARY_FCS_CRC_OK(rxBuf); //讀取CRC校驗結果 /** See if the frame should be passed up to high-level MAC. If the CRC is OK, the* the frame is always passed up. Frames with a bad CRC are also passed up *if** a special variant of promiscuous mode is active.*///add by jionghong// rxPromiscuousMode = MAC_PROMISCUOUS_MODE_WITH_BAD_CRC;if ( crcOK || (rxPromiscuousMode == MAC_PROMISCUOUS_MODE_WITH_BAD_CRC)) //如果CRC校驗通過，且是非混雜模式{int8 rssiDbm;uint8 corr;/** As power saving optimization, set state variable to indicate physical receive* has completed and then request turning of the receiver. This means the receiver* can be off (if other conditions permit) during execution of the callback function.** The receiver will be requested to turn off once again at the end of the receive* logic. There is no harm in doing this.*/macRxActive = MAC_RX_ACTIVE_DONE;macRxOffRequest();/* decode RSSI and correlation values */rssiDbm = PROPRIETARY_FCS_RSSI(rxBuf) + MAC_RADIO_RSSI_OFFSET; //提取RSSI值，并加上offestMAC_RADIO_RSSI_LNA_OFFSET(rssiDbm);corr = PROPRIETARY_FCS_CORRELATION_VALUE(rxBuf); //提取correlation值/* Read the source matching result back */if( macSrcMatchIsEnabled && MAC_RADIO_SRC_MATCH_RESULT() ){/* This result will not overwrite the previously determined pRxBuf->internal.flags */ackWithPending = MAC_RX_FLAG_ACK_PENDING;}/* record parameters that get passed up to high-level */pRxBuf->internal.flags |= ( crcOK | ackWithPending );pRxBuf->mac.mpduLinkQuality = macRadioComputeLQI(rssiDbm, corr);pRxBuf->mac.rssi = rssiDbm;pRxBuf->mac.correlation = corr;/* set the MSDU pointer to point at start of data */pRxBuf->msdu.p = (uint8 *) (pRxBuf + 1);/* finally... execute callback function */macRxCompleteCallback(pRxBuf);pRxBuf = NULL; /* needed to indicate buffer is no longer allocated */}else//如果CRC出錯{/** The CRC is bad so no ACK was sent. Cancel any callback and clear the flag.* (It's OK to cancel the outgoing ACK even if an ACK was not requested. It's* slightly more efficient to do so.)*/MAC_RADIO_CANCEL_ACK_TX_DONE_CALLBACK();macRxOutgoingAckFlag = 0;/* the CRC failed so the packet must be discarded */MEM_FREE((uint8 **)&pRxBuf);pRxBuf = NULL; /* needed to indicate buffer is no longer allocated */}/* reset threshold level, reset receive state, and complete receive logic */MAC_RADIO_SET_RX_THRESHOLD(RX_THRESHOLD_START_LEN); //一個接收任務完成，重置一些初始值pFuncRxState = &rxStartIsr; //pFuncRxState函數指針指向處剛接收packet的中斷服務程序rxStartIsrrxDone();
}/*=================================================================================================* @fn rxDone** @brief Common exit point for receive.** @param none** @return none*=================================================================================================*/staticvoid rxDone(void)
{/* if the receive FIFO has overflowed, flush it here */if (MAC_RADIO_RX_FIFO_HAS_OVERFLOWED()){MAC_RADIO_FLUSH_RX_FIFO();}/* mark receive as inactive */macRxActive = MAC_RX_ACTIVE_NO_ACTIVITY;/* if there is no outgoing ACK, run the post receive updates */if (!macRxOutgoingAckFlag){rxPostRxUpdates();}
}/*************************************************************************************************** @fn macRxAckTxDoneCallback** @brief Function called when the outoing ACK has completed transmitting.** @param none** @return none***************************************************************************************************/void macRxAckTxDoneCallback(void)
{macRxOutgoingAckFlag = 0;/** With certain interrupt priorities and timing conditions, it is possible this callback* could be executed before the primary receive logic completes. To prevent this, the* post updates are only executed if receive logic is no longer active. In the case the* post updates are not executed here, they will execute when the main receive logic* completes.*/if (!macRxActive){rxPostRxUpdates();}
}/*=================================================================================================* @fn rxPostRxUpdates** @brief Updates that need to be performed once receive is complete.** It is not fatal to execute this function if somehow receive is active. Under* certain timing/interrupt conditions a new receive may have started before this* function executes. This should happen very rarely (if it happens at all) and* would cause no problems.** @param none** @return none*=================================================================================================*/staticvoid rxPostRxUpdates(void)
{/* turn off receiver if permitted */macRxOffRequest();/* update the transmit power, update may have been blocked by transmit of outgoing ACK */macRadioUpdateTxPower();/* initiate and transmit that was queued during receive */macTxStartQueuedFrame();
}/*=================================================================================================* @fn rxDiscardFrame** @brief Initializes for discarding a packet. Must be called before ACK is strobed.** @param none** @return none*=================================================================================================*/staticvoid rxDiscardFrame(void)
{MAC_ASSERT(pFuncRxState == &rxStartIsr); /* illegal state for calling discard frame function */if (rxUnreadLen == 0){rxDone();}else{rxNextLen = MIN(rxUnreadLen, MAX_PAYLOAD_BYTES_READ_PER_INTERRUPT);MAC_RADIO_SET_RX_THRESHOLD(rxNextLen);pFuncRxState = &rxDiscardIsr;}
}/*=================================================================================================* @fn rxDiscardIsr** @brief Receive ISR state for discarding a packet.** @param none** @return none*=================================================================================================*/staticvoid rxDiscardIsr(void)
{uint8 buf[MAX_PAYLOAD_BYTES_READ_PER_INTERRUPT];MAC_RADIO_READ_RX_FIFO(buf, rxNextLen);rxUnreadLen -= rxNextLen;/* read out and discard bytes until all bytes of packet are disposed of */if (rxUnreadLen != 0){if (rxUnreadLen < MAX_PAYLOAD_BYTES_READ_PER_INTERRUPT){rxNextLen = rxUnreadLen;MAC_RADIO_SET_RX_THRESHOLD(rxNextLen);}}else{/* reset threshold level, reset receive state, and complete receive logic */MAC_RADIO_SET_RX_THRESHOLD(RX_THRESHOLD_START_LEN);pFuncRxState = &rxStartIsr;rxDone();}
}/*************************************************************************************************** @fn maxRxRifoOverflowIsr** @brief This interrupt service routine is called when RX FIFO overflow. Note that this* exception does not retrieve the good frames that are trapped in the RX FIFO.* It simply halts and cleanup the RX.** @param none** @return none***************************************************************************************************/
MAC_INTERNAL_API void macRxFifoOverflowIsr(void)
{rxFifoOverflowCount++; /* This flag is used for debug purpose only */macRxHaltCleanup();
}/*************************************************************************************************** @fn macRxPromiscuousMode** @brief Sets promiscuous mode - enabling or disabling it.** @param none** @return none***************************************************************************************************/
MAC_INTERNAL_API void macRxPromiscuousMode(uint8 mode)
{rxPromiscuousMode = mode;if (rxPromiscuousMode == MAC_PROMISCUOUS_MODE_OFF){MAC_RADIO_TURN_ON_RX_FRAME_FILTERING(); //關閉混雜模式}else{MAC_ASSERT((mode == MAC_PROMISCUOUS_MODE_WITH_BAD_CRC) ||(mode == MAC_PROMISCUOUS_MODE_COMPLIANT)); /* invalid mode */MAC_RADIO_TURN_OFF_RX_FRAME_FILTERING(); //開啟混雜模式}
}/*************************************************************************************************** Compile Time Integrity Checks***************************************************************************************************//* check for changes to the spec that would affect the source code */
#if ((MAC_A_MAX_PHY_PACKET_SIZE != 0x7F ) || \(MAC_FCF_FIELD_LEN != 2 ) || \(MAC_FCF_FRAME_TYPE_POS != 0 ) || \(MAC_FCF_FRAME_PENDING_POS != 4 ) || \(MAC_FCF_ACK_REQUEST_POS != 5 ) || \(MAC_FCF_INTRA_PAN_POS != 6 ) || \(MAC_FCF_DST_ADDR_MODE_POS != 10 ) || \(MAC_FCF_FRAME_VERSION_POS != 12 ) || \(MAC_FCF_SRC_ADDR_MODE_POS != 14 ))
#error "ERROR! Change to the spec that requires modification of source code."
#endif/* check for changes to the internal flags format */
#if ((MAC_RX_FLAG_VERSION != 0x03) || \(MAC_RX_FLAG_ACK_PENDING != 0x04) || \(MAC_RX_FLAG_SECURITY != 0x08) || \(MAC_RX_FLAG_PENDING != 0x10) || \(MAC_RX_FLAG_ACK_REQUEST != 0x20) || \(MAC_RX_FLAG_INTRA_PAN != 0x40))
#error "ERROR! Change to the internal RX flags format. Requires modification of source code."
#endif/* validate CRC OK bit optimization */
#if (MAC_RX_FLAG_CRC_OK != PROPRIETARY_FCS_CRC_OK_BIT)
#error "ERROR! Optimization relies on these bits having the same position."
#endif#if (MAC_RX_ACTIVE_NO_ACTIVITY != 0x00)
#error "ERROR! Zero is reserved value of macRxActive. Allows boolean operations, e.g !macRxActive."
#endif#if (MAC_PROMISCUOUS_MODE_OFF != 0x00)
#error "ERROR! Zero is reserved value of rxPromiscuousMode. Allows boolean operations, e.g !rxPromiscuousMode."
#endif/**************************************************************************************************
*/
