【STM32G0B1 FDCAN调试深度详解】_业界新闻

发布时间:2024-08-04 03:37

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STM32G0B1 FDCAN调试深度详解

目录
- 1.FDCAN模块featurelist
- 2.初始化配置
- - 1.CAN波特率配置
  - 2.采样点配置
  - 3.其他配置
- 3.过滤配置
- - 1.不需要ID过滤，即全部接受
  - 2.只接受某些ID
- 4.中断配置
- 5.数据发送

STM32G0B1集成2路独立(相对STM32F10系列2路是非完全独立的)的CANFD模块
1.2个接收FIFO，每个FIFO有3级深度
2.1个发送FIFO，3级深度，可配置发送优先级
3.1个Tx Event FIFO(暂未研究应用场景)
4.2个中断线，可配置中断关联哪个中断线
5.强大且灵活的过滤器，标准帧有28个过滤器，扩展帧有8个过滤器

2.初始化配置

初始化可以基于cubmx进行配置

各个参数如下

  uint32_t ClockDivider;                 /*!< Specifies the FDCAN kernel clock divider.                                               The clock is common to all FDCAN instances.                                               This parameter is applied only at initialisation of                                               first FDCAN instance.                                               This parameter can be a value of @ref FDCAN_clock_divider.   */    uint32_t FrameFormat;                  /*!< Specifies the FDCAN frame format.                                               This parameter can be a value of @ref FDCAN_frame_format     */    uint32_t Mode;                         /*!< Specifies the FDCAN mode.                                               This parameter can be a value of @ref FDCAN_operating_mode   */    FunctionalState AutoRetransmission;    /*!< Enable or disable the automatic retransmission mode.                                               This parameter can be set to ENABLE or DISABLE               */    FunctionalState TransmitPause;         /*!< Enable or disable the Transmit Pause feature.                                               This parameter can be set to ENABLE or DISABLE               */    FunctionalState ProtocolException;      /*!< Enable or disable the Protocol Exception Handling.                                               This parameter can be set to ENABLE or DISABLE               */    uint32_t NominalPrescaler;             /*!< Specifies the value by which the oscillator frequency is                                               divided for generating the nominal bit time quanta.                                               This parameter must be a number between 1 and 512            */    uint32_t NominalSyncJumpWidth;         /*!< Specifies the maximum number of time quanta the FDCAN                                               hardware is allowed to lengthen or shorten a bit to perform                                               resynchronization.                                               This parameter must be a number between 1 and 128            */    uint32_t NominalTimeSeg1;              /*!< Specifies the number of time quanta in Bit Segment 1.                                               This parameter must be a number between 2 and 256            */    uint32_t NominalTimeSeg2;              /*!< Specifies the number of time quanta in Bit Segment 2.                                               This parameter must be a number between 2 and 128            */    uint32_t DataPrescaler;                /*!< Specifies the value by which the oscillator frequency is                                               divided for generating the data bit time quanta.                                               This parameter must be a number between 1 and 32             */    uint32_t DataSyncJumpWidth;            /*!< Specifies the maximum number of time quanta the FDCAN                                               hardware is allowed to lengthen or shorten a data bit to                                               perform resynchronization.                                               This parameter must be a number between 1 and 16             */    uint32_t DataTimeSeg1;                 /*!< Specifies the number of time quanta in Data Bit Segment 1.                                               This parameter must be a number between 1 and 32             */    uint32_t DataTimeSeg2;                 /*!< Specifies the number of time quanta in Data Bit Segment 2.                                               This parameter must be a number between 1 and 16             */    uint32_t StdFiltersNbr;                /*!< Specifies the number of standard Message ID filters.                                               This parameter must be a number between 0 and 28             */    uint32_t ExtFiltersNbr;                /*!< Specifies the number of extended Message ID filters.                                               This parameter must be a number between 0 and 8             */    uint32_t TxFifoQueueMode;              /*!< Tx FIFO/Queue Mode selection.                                               This parameter can be a value of @ref FDCAN_txFifoQueue_Mode */

这里重点讲以下几点：

1.CAN波特率配置

CAN的时钟源有三个，分别是PCLK，PLLQ，HSE，根据需要选择，假定选的是PCLK=64M，那么
仲裁域baud=64M/ClockDivider(only CAN1，CAN2固定为1) / NominalPrescaler / (1+NominalTimeSeg1+NominalTimeSeg2) = 64M/1/4/(1+27+4)=500K
数据域boud=64M/ClockDivider(only CAN1，CAN2固定为1)/DataPrescaler/(1+DataTimeSeg1+DataTimeSeg2) = 64M/1/2/(1+25+5)=1M其中以上几个参数有一下注意事项：
1)仲裁域波特率/数据域波特率 >= 1/8，比如仲裁域500K，数据域最多不超过4M
2)仲裁域和数据域的跳跃段SyncJumpWidth分别<=各自的TimeSeg2

2.采样点配置

仲裁域和数据域的采样点 = (1+Seg1)/(1+Seg1+Seg2)，仲裁域和数据域的采样点可以不相同，但要遵循以下范围：
baud > 800K: 75%
baud > 500K:80%
baud <= 500K: 87.5%

3.其他配置

FrameFormat：配置传统can模式还是canfd模式，建议canfd，因为canfd兼容can模式(可以收发传统can报文)
AutoRetransmission：配置can发送时，未收到ack是否重复，一般配置重发
TransmitPause：配置是否允许发送暂停，一般不需要
ProtocolException：一般不需要
StdFiltersNbr：配置标准帧过滤器个数，最多28个，如果不用id过滤功能，不用关心。
ExtFiltersNbr：配置扩展帧过滤器个数，最多8个，如果不用id过滤功能，不用关心。
TxFifoQueueMode：配置发送模式，一般配置fifo就行了，即根据写入txfifo先后顺序发送报文。但有些应用场景需要后塞入发送fifo的报文，根据id或其他特性需要优先发送的场景，结合这个参数的配置可以满足

3.过滤配置

STM32G0的过滤器是我目前用过最好用的filter，主要有以下特点
1.标准帧和扩展帧的分别可以配置，包括使用过滤器的个数和每个过滤器的模式
2.支持[ID1,ID2]这种范围过滤
3.支持双过滤ID1，ID2满足任意即可(范围已经包含这种模式)
4.传统的filter，mask模式，即mask某位为1，则需要匹配对应的filter为；mask某位为0，则不用关心
5.通过过滤器的报文可以指定到进入那个FIFO，同时还支持相关优先级的配置，可以参考手册SFEC/EFEC位。

应用举例，

1.不需要ID过滤，即全部接受

不用配置过滤器，直接调用

HAL_StatusTypeDef HAL_FDCAN_ConfigGlobalFilter(FDCAN_HandleTypeDef *hfdcan, FDCAN_ACCEPT_IN_RX_FIFO0 ,FDCAN_ACCEPT_IN_RX_FIFO0 , FDCAN_FILTER_REMOTE,                                                FDCAN_FILTER_REMOTE )

允许接受所有的标准帧和扩展帧以及各自的远程帧即可

2.只接受某些ID

使用下面接口配置标准帧过滤，使用那个过滤器(如果StdFiltersNbr配置为3，那么可使用的过滤器分别是0，1，2)

HAL_StatusTypeDef HAL_FDCAN_ConfigFilter(FDCAN_HandleTypeDef *hfdcan, const FDCAN_FilterTypeDef *sFilterConfig)  typedef struct {   uint32_t IdType;           //配置标准帧或扩展帧    uint32_t FilterIndex;      //0~StdFiltersNbr-1或0~ExtFiltersNbr-1    uint32_t FilterType;       //范围、双id、传统屏蔽方式    uint32_t FilterConfig;     //通过过滤器不进或进入rxfifo0或rxfifo1及是否设置优先级    uint32_t FilterID1;        /*!< Specifies the filter identification 1.                                   This parameter must be a number between:                                    - 0 and 0x7FF, if IdType is FDCAN_STANDARD_ID                                    - 0 and 0x1FFFFFFF, if IdType is FDCAN_EXTENDED_ID       */    uint32_t FilterID2;        /*!< Specifies the filter identification 2.                                   This parameter must be a number between:                                    - 0 and 0x7FF, if IdType is FDCAN_STANDARD_ID                                    - 0 and 0x1FFFFFFF, if IdType is FDCAN_EXTENDED_ID       */  } FDCAN_FilterTypeDef;

如果需要设置多个规则，多次调用该接口，保证每次设置的FilterIndex不同(标准帧和扩展帧有各自的FilterIndex 0-27或0-7)

进行全局滤波器设置，设置标准和扩展的远程帧，设置标准和扩展的未通过滤波器的报文如何处理

HAL_StatusTypeDef HAL_FDCAN_ConfigGlobalFilter(FDCAN_HandleTypeDef *hfdcan, FDCAN_ACCEPT_IN_RX_FIFO0 ,FDCAN_ACCEPT_IN_RX_FIFO0 , FDCAN_FILTER_REMOTE,                                                FDCAN_FILTER_REMOTE )

比如设置某些id通过滤波器进入FIFO0，按照一般的设计，不通过滤波器的默认就被丢弃了，而STM32G0B1的FDCAN可以设置不通过滤波器的报文如何处理:拒绝或者进入FIFO0或FIFO1，这个机制对于某些应用设置ID白名单或黑名单或进行高级分组非常有效。

附RxFIFO及过滤器等位域定义

typedef struct{ 	union { 		uint32_t Raw; 		struct { 			union { 				uint32_t S0; 				struct { 					uint32_t SFID2:11; 					uint32_t      :5; 					uint32_t SFID1:11; 					uint32_t SFEC :3; 					uint32_t SFT  :2; 				} S0Bit; 			} S0; 		} Head; 	} StdFilter[28];//Standard Filter element 	union { 		uint32_t Raw[2]; 		struct { 			union { 				uint32_t F0; 				struct { 					uint32_t EFID1:29; 					uint32_t EFEC :3; 				} F0Bit; 			} F0; 			union { 				uint32_t F1; 				struct { 					uint32_t EFID2:29; 					uint32_t      :1; 					uint32_t EFT  :2; 				} F1Bit; 			} F1; 		} Head; 	} ExtFilter[8];//Extended Filter element 	union { 		uint32_t Raw[18];//占位 		struct { 			union { 				uint32_t R0;//占位 				struct { 					uint32_t    :18; 					uint32_t ID :11;//Identifier 					uint32_t RTR:1;//Received frame is a remote frame 					uint32_t XTD:1;//Extended identifier 					uint32_t ESI:1;//Error state indicator 				} R0BitS; 				struct { 					uint32_t ID :29;//Identifier 					uint32_t RTR:1;//Received frame is a remote frame 					uint32_t XTD:1;//Extended identifier 					uint32_t ESI:1;//Error state indicator 				} R0BitE; 			} R0; 			union { 				uint32_t R1;//占位 				struct { 					uint32_t RXTS:16;//Rx timestamp 					uint32_t DLC :4; 					uint32_t BRS :1;//Frame received with bit rate switching 					uint32_t FDF :1;//FDCAN frame format (new DLC-coding and CRC) 					uint32_t     :2; 					uint32_t FIDX:7;//Filter index 					uint32_t ANMF:1;//Received frame did not match any Rx filter element 				} R1Bit; 			} R1; 			uint8_t Data[64]; 		} Head; 	} RxFifo[2][3];//RxFIFO0和1 	union { 		uint32_t Raw[2]; 		struct { 			union { 				uint32_t E0; 				struct { 					uint32_t ID:29;//Identifier 					uint32_t RTR:1;//Received frame is a remote frame 					uint32_t XTD:1;//Extended identifier 					uint32_t ESI:1;//Error state indicator 				} E0Bit; 			} E0; 			union { 				uint32_t E1; 				struct { 					uint32_t TXTS:16; 					uint32_t DLC :4; 					uint32_t BRS :1; 					uint32_t EDF :1; 					uint32_t ET  :2; 					uint32_t MM  :8; 				} E1Bit; 			} E1; 		} Head; 	} TxEventFifo[3];//Tx Event FIFO 	union { 		uint32_t Raw[18];//占位 		struct { 			union { 				uint32_t T0; 				struct { 					uint32_t ID:29;//Identifier 					uint32_t RTR:1;//Received frame is a remote frame 					uint32_t XTD:1;//Extended identifier 					uint32_t ESI:1;//Error state indicator 				} T0Bit; 			} T0; 			union { 				uint32_t T1; 				struct { 					uint32_t    :16; 					uint32_t DLC:4; 					uint32_t BRS:1;//CAN FD frames transmitted with bit rate switching 					uint32_t FDF:1;//Frame transmitted in CAN FD format 					uint32_t    :1; 					uint32_t EFC:1;//Store Tx events 					uint32_t MM:8;//Message marker 				} T1Bit; 			} T1; 			uint8_t  Data[64]; 		} Head; 	} TxQueueFifo[3];//Tx FIFO/Queue } Stm32g_FdcanMbType;

如果想读rxfifo中的数据，使用该类型指针强行指向下面这个地址
#define SRAMCAN_BASE (APBPERIPH_BASE + 0x0000B400UL)
对于CAN2，加上sizeof(Stm32g_FdcanMbType)偏移即可，特别注意，m0不支持非对其访问，不可使用位域进行写操作!!!

4.中断配置

由于STM32G0B1是M0+内核，基于成本考虑，CAN1和CAN2的中断线0，CAN1和CAN2的的中断线1是同一个中断源

  .word TIM16_FDCAN_IT0_IRQHandler        /* TIM16 & FDCAN1_IT0 & FDCAN2_IT0 */   .word TIM17_FDCAN_IT1_IRQHandler        /* TIM17 & FDCAN1_IT1 & FDCAN2_IT1 */

如果同时使用CAN1和CAN2，建议CAN1使用中断线0，CAN2使中断线1，这样的好处是中断里不用判断到底是CAN1还是CAN2了，可以提升性能。注意，FIFO0&FIF01和IL0&IL1是无关的，不是FIFO0对应IL0的。

HAL_StatusTypeDef HAL_FDCAN_ConfigInterruptLines(FDCAN_HandleTypeDef *hfdcan, uint32_t ITList, uint32_t InterruptLine)

使能接收中断接口

HAL_StatusTypeDef HAL_FDCAN_ActivateNotification(FDCAN_HandleTypeDef *hfdcan, uint32_t ActiveITs,                                                  uint32_t BufferIndexes)

读取中断里接受的报文

HAL_StatusTypeDef HAL_FDCAN_GetRxMessage(FDCAN_HandleTypeDef *hfdcan, uint32_t RxLocation,                                          FDCAN_RxHeaderTypeDef *pRxHeader, uint8_t *pRxData)

5.数据发送

HAL_StatusTypeDef HAL_FDCAN_AddMessageToTxFifoQ(FDCAN_HandleTypeDef *hfdcan, const FDCAN_TxHeaderTypeDef *pTxHeader,                                                 const uint8_t *pTxData)