SAM9G45之USB学习笔记

秒速五厘米 2022-06-02 09:12 149阅读 0赞

最近一直在学习SAM9G45的USB功能，资料大部分都是从网上找的，还有就是官方给的库，只是把自己调试过程中遇到的问题记录下来，因为没有调试完，所以会持续更新。

问题一（其实也不是问题），SAM9G45只有7个端点（包括端点0），我开始调试的时候以为不带0，哎，郁闷。

问题二（待求证），不过从我目前的调试来看，结论是对的。SAM9G45的端点不是全双工了，一个端点不能同时配置为IN和OUT，但是手册又有自相矛盾的地方。

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从表38-1来看它的每个端点都支持ctrl传输模式，根据USB协议规定，这个传输模式要求端点必须是全双工的，因为ctrl的端点必须支持messsge pipe类型。

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从表38-2也能看出，CTRL模式是双向的；

![SouthEast 2][]

从表38-3的注意1来看，它说control transfer必须是1bank，从38-1看，bank1只能是端点0；从这里来看其它端点是不能支持ctrl模式的。和我的实验结论一致，也可能是我不会设置端点地址，如果哪位网友正好知道，请给我留言，谢谢。

三、Bus Hound配置问题

这个东西用的不熟悉，抓包发现只能抓取32的字节的IN指令包，以为是设备问题，最后发现是busHound设置问题，郁闷。

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四、这个是目前遇到最郁闷的问题

刚开始的Demo是hid\_transfer，我在这个基础上改的CCID，并且开始只是用一个设备+一个interface调试的，很顺利，很快就识别出来了。应用需求，需要两个interface，改过之后怎么也识别不了第二个设备。Bus Hound上面，也没有第二个设备的报文。郁闷，以为是配置问题，结果把配置复制带interface0上面，正常。郁闷了，所有的操作函数都是一套，通过接口传参数，来确定是操作那个设备，难道个别的函数有错误，参数没有改过来？于是把所有的函数全部对了一遍，没有错误啊？这是怎么回事。最后找到原因了，原来是windows系统的驱动问题。如果一个设备的V\_ID和P\_ID不修改，之前已经插入过电脑，并且正确设别并安装驱动的话，如果再次插入（即使配置付改变了）驱动不会从新安装，这个时候设备出来的还是原来的设备。

解决方法：

1、修改P\_ID或者V\_ID的值；

2、或者在注册表里面删掉对应的配置信息；

我修改了P\_ID值，正确识别了两个设备：

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《-------------------------------------------------------------------------------------------------------》

官方USB协议帧学习笔记：

先上传几张图片，回头再整理：

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图1 协议栈的结构

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图2 USB的状态机

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图3 USB的协议栈回调函数架构

首先要知道USB的驱动状态：

USB device states  
/// The device is currently suspended.  
\#define USBD\_STATE\_SUSPENDED 0  
/// USB cable is plugged into the device.  
\#define USBD\_STATE\_ATTACHED 1  
/// Host is providing +5V through the USB cable.  
\#define USBD\_STATE\_POWERED 2  
/// Device has been reset.  
\#define USBD\_STATE\_DEFAULT 3  
/// The device has been given an address on the bus.  
\#define USBD\_STATE\_ADDRESS 4  
/// A valid configuration has been selected.  
\#define USBD\_STATE\_CONFIGURED 5  
  
deviceState（状态变量）

其次USB的API返回值

USB device API return values  
/// Indicates the operation was successful.  
\#define USBD\_STATUS\_SUCCESS 0  
/// Endpoint/device is already busy.  
\#define USBD\_STATUS\_LOCKED 1  
/// Operation has been aborted.  
\#define USBD\_STATUS\_ABORTED 2  
/// Operation has been aborted because the device has been reset.  
\#define USBD\_STATUS\_RESET 3  
/// Operation failed because parameter error  
\#define USBD\_STATUS\_INVALID\_PARAMETER 4  
/// Operation failed because HW not supported  
\#define USBD\_STATUS\_HW\_NOT\_SUPPORTED 5

端点的状态：

Endpoint states  
/// Endpoint states: Endpoint is disabled  
\#define UDP\_ENDPOINT\_DISABLED 0  
/// Endpoint states: Endpoint is halted (i.e. STALLs every request)  
\#define UDP\_ENDPOINT\_HALTED 1  
/// Endpoint states: Endpoint is idle (i.e. ready for transmission)  
\#define UDP\_ENDPOINT\_IDLE 2  
/// Endpoint states: Endpoint is sending data  
\#define UDP\_ENDPOINT\_SENDING 3  
/// Endpoint states: Endpoint is receiving data  
\#define UDP\_ENDPOINT\_RECEIVING 4

1、CCIDDriver\_Initialize()

CCIDDriver\_Initialize()->USBD\_Init()->USBDCallbacks\_Initialized()->IRQ\_ConfigureIT(AT91C\_ID\_UDPHS, 0, UDPD\_IrqHandler);//, UDPD\_IrqHandler);

把UDPD\_IrqHandler()配置为USB的中断函数；

UDPD\_IrqHandler()调用UDPHS\_EndpointHandler()和UDPHS\_DmaHandler()

其中：

UDPHS\_EndpointHandler()->USBDCallbacks\_RequestReceived()->CCID\_RequestHandler()->CCID

处理和USBDDriver\_RequestHandler()

UDPHS\_EndpointHandler()和UDPHS\_DmaHandler()都会调用UDPHS\_EndOfTransfer()

来看下UDPHS\_EndOfTransfer()

//------------------------------------------------------------------------------
    /// Handles a completed transfer on the given endpoint, invoking the
    /// configured callback if any.
    /// \param bEndpoint Number of the endpoint for which the transfer has completed.
    /// \param bStatus   Status code returned by the transfer operation
    //------------------------------------------------------------------------------
    static void UDPHS_EndOfTransfer( unsigned char bEndpoint, char bStatus )
    {
        Endpoint *pEndpoint = &(endpoints[bEndpoint]);
        Transfer *pTransfer = &(pEndpoint->transfer);
    
        // Check that endpoint was sending or receiving data
        if( (pEndpoint->state == UDP_ENDPOINT_RECEIVING)
         || (pEndpoint->state == UDP_ENDPOINT_IDLE)
         || (pEndpoint->state == UDP_ENDPOINT_SENDING) ) {
    
            TRACE_DEBUG_WP("UDPHS_EndOfTransfer ");
            if(pEndpoint->state == UDP_ENDPOINT_SENDING) {
                pEndpoint->sendZLP = 0;
            }
            // Endpoint returns in Idle state
            //if(pEndpoint->state == UDP_ENDPOINT_SENDING){
                pEndpoint->state = UDP_ENDPOINT_IDLE;
            //}
    
            // Invoke callback is present
            if (pTransfer->fCallback != 0) {
    
                ((TransferCallback) pTransfer->fCallback)
                    (pTransfer->pArgument,
                     bStatus,
                     pTransfer->transferred,
                     pTransfer->remaining + pTransfer->buffered);
            }
            else {
                TRACE_DEBUG_WP("No callBack\n\r");
            }
        }
    }

当接收完成或者发送完成，就会调用一个callback，这个callback是哪里来的呢？继续看

void CCID_SmartCardRequest_V1( uint8_t   chCcidNum )
    {
        unsigned char bStatus;
        if(chCcidNum >= CCID_INTERFACE_NUM){
            TRACE_ERROR("CCID_SmartCardRequest  chCcidNum >= CCID_INTERFACE_NUM\n\r");
            return;
        }
        //do{
    
            bStatus = CCID_Read_V1((void*)&ccidDriver.tCcidStruct[chCcidNum].sCcidCommand,
                                 sizeof(S_ccid_bulk_out_header),
                                 (TransferCallback)&CCIDCommandDispatcher_V1,
                                 (void*)chCcidNum );//直接把值变为地址传输
        //}while (bStatus != USBD_STATUS_SUCCESS);
    
    }

这个是API层的CCID调用函数，

//------------------------------------------------------------------------------
    /// Reads data from the Data OUT endpoint
    /// \param pBuffer   Buffer to store the received data
    /// \param dLength   data buffer length
    /// \param fCallback Optional callback function
    /// \param pArgument Optional parameter for the callback function
    /// \return USBD_STATUS_LOCKED or USBD_STATUS_SUCCESS
    //------------------------------------------------------------------------------
    /*
    unsigned char CCID_Read(void *pBuffer,
                            unsigned int dLength,
                            TransferCallback fCallback,
                            void *pArgument)
    {
        return USBD_Read(CCID_EPT_DATA_OUT, pBuffer, dLength, fCallback, pArgument);
    }*/
    
    
    unsigned char CCID_Read_V1( void *pBuffer,
                                unsigned int dLength,
                                TransferCallback fCallback,
                                void *pArgument)
    {
        uint8_t chEndpointOut = 0;
    
        if(((uint8_t)pArgument) >= CCID_INTERFACE_NUM){
            TRACE_ERROR("CCID_Read  chCcidNum >= CCID_INTERFACE_NUM\n\r");
            return USBD_STATUS_INVALID_PARAMETER;
        }
    
        switch((uint8_t)pArgument){
    #if (CCID_INTERFACE_NUM>0)
        case 0:
            chEndpointOut = CCID_INTERFACE0_EPT_DATA_OUT;
            break;
    #endif
    #if (CCID_INTERFACE_NUM>1)
        case 1:
            chEndpointOut = CCID_INTERFACE1_EPT_DATA_OUT;
            break;
    #endif
    #if (CCID_INTERFACE_NUM>2)
        case 2:
            chEndpointOut = CCID_INTERFACE2_EPT_DATA_OUT;
            break;
    #endif
    #if (CCID_INTERFACE_NUM>3)
        case 3:
            chEndpointOut = CCID_INTERFACE3_EPT_DATA_OUT;
            break;
    #endif
        }
    
        return USBD_Read(chEndpointOut, pBuffer, dLength, fCallback, pArgument);
    }

继续看：

//------------------------------------------------------------------------------
    /// Reads incoming data on an USB endpoint (OUT)
    /// \param bEndpoint Index of endpoint
    /// \param *pData  Data to be readen
    /// \param dLength Data length to be receive
    /// \param fCallback  Callback to be call after the success command
    /// \param *pArgument Callback argument
    /// \return USBD_STATUS_LOCKED or USBD_STATUS_SUCCESS
    //------------------------------------------------------------------------------
    char USBD_Read( unsigned char    bEndpoint,
                    void             *pData,
                    unsigned int     dLength,
                    TransferCallback fCallback,
                    void             *pArgument )
    {
        Endpoint *pEndpoint = &(endpoints[bEndpoint]);
        Transfer *pTransfer = &(pEndpoint->transfer);
      
        // Return if the endpoint is not in IDLE state
        if (pEndpoint->state != UDP_ENDPOINT_IDLE) {
    
            return USBD_STATUS_LOCKED;
        }
    
        TRACE_DEBUG_WP("Read%d(%d) ", bEndpoint, dLength);
    
        // Endpoint enters Receiving state
        pEndpoint->state = UDP_ENDPOINT_RECEIVING;
    
        // Set the transfer descriptor
        pTransfer->pData = pData;
        pTransfer->remaining = dLength;
        pTransfer->buffered = 0;
        pTransfer->transferred = 0;
        pTransfer->fCallback = fCallback;
        pTransfer->pArgument = pArgument;
    
    #ifdef DMA
        // Test if endpoint type control
        if(AT91C_UDPHS_EPT_TYPE_CTL_EPT == (AT91C_UDPHS_EPT_TYPE&(AT91C_BASE_UDPHS->UDPHS_EPT[bEndpoint].UDPHS_EPTCFG))) {
    #endif
            // Control endpoint
            // Enable endpoint IT
            AT91C_BASE_UDPHS->UDPHS_IEN |= (1 << SHIFT_INTERUPT << bEndpoint);
            AT91C_BASE_UDPHS->UDPHS_EPT[bEndpoint].UDPHS_EPTCTLENB = AT91C_UDPHS_RX_BK_RDY;
    #ifdef DMA
        }
        else {
    
            TRACE_DEBUG_WP("Read%d(%d) ", bEndpoint, dLength);
    
            // Others endpoints (not control)
            if( pTransfer->remaining > DMA_MAX_FIFO_SIZE ) {
    
                // Transfer the max
                pTransfer->buffered = DMA_MAX_FIFO_SIZE;    
            }
            else {
                // Transfer the good size
                pTransfer->buffered = pTransfer->remaining;
            }
    
            AT91C_BASE_UDPHS->UDPHS_DMA[bEndpoint].UDPHS_DMAADDRESS = (unsigned int)(pTransfer->pData);
    
            // Clear unwanted interrupts
            AT91C_BASE_UDPHS->UDPHS_DMA[bEndpoint].UDPHS_DMASTATUS;
    
            // Enable DMA endpoint interrupt
            AT91C_BASE_UDPHS->UDPHS_IEN |= (1 << SHIFT_DMA << bEndpoint);
    
            TRACE_DEBUG_WP("\n\r_RR:%d ", pTransfer->remaining );
            TRACE_DEBUG_WP("B:%d ", pTransfer->buffered );
            TRACE_DEBUG_WP("T:%d ", pTransfer->transferred );
    
            // DMA config
            AT91C_BASE_UDPHS->UDPHS_DMA[bEndpoint].UDPHS_DMACONTROL = 0; // raz
            AT91C_BASE_UDPHS->UDPHS_DMA[bEndpoint].UDPHS_DMACONTROL =
                                     ( ((pTransfer->buffered << 16) & AT91C_UDPHS_BUFF_COUNT)
                                       | AT91C_UDPHS_END_TR_EN
                                       | AT91C_UDPHS_END_TR_IT
                                       | AT91C_UDPHS_END_B_EN
                                       | AT91C_UDPHS_END_BUFFIT
                                       | AT91C_UDPHS_CHANN_ENB );
        }
    #endif
    
        return USBD_STATUS_SUCCESS;
    }

到这看明白了吧，是上层的CCID\_SmartCardRequest\_V1()通过usb\_read()设置的

看下端点的结构体：

//------------------------------------------------------------------------------
    /// Describes the state of an endpoint of the UDP controller.
    //------------------------------------------------------------------------------
    typedef struct
    {
        /// Current endpoint state.
        volatile unsigned char  state;
        /// Current reception bank (0 or 1).
        unsigned char  bank;
        /// Maximum packet size for the endpoint.
        unsigned short size;
        /// Describes an ongoing transfer (if current state is either
        ///  <UDP_ENDPOINT_SENDING> or <UDP_ENDPOINT_RECEIVING>)
        Transfer       transfer;
        /// Special case for send a ZLP
        unsigned char  sendZLP;
    } Endpoint;

/// Describes an ongoing transfer on a UDP endpoint.
    typedef struct
    {
        /// Pointer to a data buffer used for emission/reception.
        char             *pData;
        /// Number of bytes which have been written into the UDP internal FIFO
        /// buffers.
        volatile int     buffered;
        /// Number of bytes which have been sent/received.
        volatile int     transferred;
        /// Number of bytes which have not been buffered/transferred yet.
        volatile int     remaining;
        /// Optional callback to invoke when the transfer completes.
        volatile TransferCallback fCallback;
        /// Optional argument to the callback function.
        void             *pArgument;
    } Transfer;

至此，我们把自己每个端点的处理函数CCIDCommandDispatcher\_V1()绑定到了相应的端点上。

问题：

1、到目前为止，有一点我不是很理解，为什么每次收到后，需要对相应的DMA重新初始化，相应的端点也同样做了初始化，我查看了HID、CDC历程，都是这么处理的。因此在CCIDCommandDispatcher\_V1()里面我们需要调用usb\_read()做相应初始化，或者利用查询方式，在应用层初始化。

<--------------------------------------------------------2021.08.05------------------------------------------------------>

一、今天测试MCU的CDC功能，在其它产品上在跑了，没问题了。但是应用到我的产品上，发现老是复位。和没有问题的产品区别：

1）它是USB数据到UART1，我是USB数据到UART3;

2）它是连接的其它UART模块，我是连接的NB；

通过屏蔽代码，发现是看门狗复位。

通过屏蔽代码，NB上电不使能，没有问题。

NB上电会通过串口往外发信息，导致MCU“死机”，看门狗复位。

在分析原因，上电USB会初始化，和上位机交互，如果这个时候应用层通过USB发送数据，会导致USB出问题。解决方案是等待USB初始化完成，才允许应用层通过USB发送数据。

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