USB Device实验程序解析

// USB device实验程序解析//头文件#include <stdint.h>#include <stdbool.h>#include <time.h>#include "inc/hw_ints.h"#include "inc/hw_memmap.h"#include "inc/hw_types.h"#include "driverlib/debug.h"#include "driverlib/fpu.h"#include "driverlib/gpio.h"#include "driverlib/interrupt.h"#include "driverlib/sysctl.h"#include "driverlib/systick.h"#include "driverlib/timer.h"#include "driverlib/uart.h"#include "driverlib/rom.h"#include "grlib/grlib.h"#include "usblib/usblib.h"#include "usblib/usb-ids.h"#include "usblib/device/usbdevice.h"#include "usblib/device/usbdbulk.h"#include "utils/uartstdio.h"#include "utils/ustdlib.h"#include "drivers/cfal96x64x16.h"#include "usb_bulk_structs.h"// 系统节拍定时systick宏定义// SYSTICKS_PER_SECOND 每秒中断次数#define SYSTICKS_PER_SECOND 100#define SYSTICK_PERIOD_MS (1000 / SYSTICKS_PER_SECOND) // 全局systick计数volatile ui32 g_ulSysTickCount = 0;//全局变量记录发送和接收字节数volatile ui32 g_ulTxCount = 0;volatile ui32 g_ulRxCount = 0;#ifdef DEBUGui32 g_ulUARTRxErrors = 0;#endif// 与debug相关的定义和声明// 如果在编译时定义了DEBUG那么通过UART0进行Debug的输出#ifdef DEBUG//将所有Debug打印请求映射到UARTprintf输出#define DEBUG_PRINT UARTprintf#else// 编译所有的Debug打印请求#define DEBUG_PRINT while(0) ((int (*)(char *, ...))0)#endif// 图形上下文（context）用于OLED屏幕显示tContext g_sContext;// 宏定义标志，用于在中断时向主程序发送命令.#define COMMAND_PACKET_RECEIVED 0x00000001#define COMMAND_STATUS_UPDATE 0x00000002volatile ui32 g_ulFlags = 0;char *g_pcStatus;// 全局标志显示USB设置是否完成static volatile bool g_bUSBConfigured = false;// 错误处理#ifdef DEBUGvoid__error__(char *pcFilename, ui32 ulLine){UARTprintf("Error at line %d of %s\n", ulLine, pcFilename);while(1){}}#endif// systick中断处理voidSysTickIntHandler(void){// 更新tick计数g_ulSysTickCount++;}//函数static ui32// 功能：device接收数据并返回给主机。

// 当从主机数据发送就绪后，该程序被调用，逐个字节读取数据，并且翻转//大小写，最后回传给主机// 变量psDevice 指向要处理的设备数据实例// 变量pcData 指向USB接收缓冲去新接收到的数据// 变量ulNumBytes 是程序要处理的字节数。

// 返回：处理的数据字节数static ui32EchoNewDataToHost(tUSBDBulkDevice *psDevice, ui8 *pcData,ui32 ulNumBytes){ui32 ulLoop, ulSpace, ulCount;ui32 ulReadIndex;ui32 ulWriteIndex;tUSBRingBufObject sTxRing;// 获取当前缓冲区信息以允许设备能直接写入发送缓冲区。

//（变量中已经有足够信息与接收缓冲区直接连接）USBBufferInfoGet(&g_sTxBuffer, &sTxRing);// 获取发送缓冲区的剩余空间ulSpace = USBBufferSpaceAvailable(&g_sTxBuffer);// 判断此次可以处理的字节数ulLoop = (ulSpace < ulNumBytes) ? ulSpace : ulNumBytes; ulCount = ulLoop;// 更新接收字节数g_ulRxCount += ulNumBytes;// 显示Debug信息DEBUG_PRINT("Received %d bytes\n", ulNumBytes);// 与USB缓冲区连接启动字节处理ulReadIndex = (ui32)(pcData - g_pucUSBRxBuffer); ulWriteIndex = sTxRing.ui32WriteIndex;while(ulLoop){ // 将接收缓冲去的字节拷入发送缓冲区// 判断是否是小写字母if((g_pucUSBRxBuffer[ulReadIndex] >= 'a') &&(g_pucUSBRxBuffer[ulReadIndex] <= 'z')){ // 转换为大写字母，写到发送缓冲区中g_pucUSBTxBuffer[ulWriteIndex] =(g_pucUSBRxBuffer[ulReadIndex] - 'a') + 'A';}else{ // 判断是否是大写字母if((g_pucUSBRxBuffer[ulReadIndex] >= 'A') &&(g_pucUSBRxBuffer[ulReadIndex] <= 'Z')){ // 转换为小写字母，写到发送缓冲区中g_pucUSBTxBuffer[ulWriteIndex] =(g_pucUSBRxBuffer[ulReadIndex] - 'Z') + 'z';}else{ // 将接收到的数据拷到发送缓冲区g_pucUSBTxBuffer[ulWriteIndex] = g_pucUSBRxBuffer[ulReadIndex];}}// 将指针移到下一字节，当移到缓冲区底时，进行对应调整ulWriteIndex++;ulWriteIndex = (ulWriteIndex == BULK_BUFFER_SIZE) ? 0 : ulWriteIndex;ulReadIndex++;ulReadIndex = (ulReadIndex == BULK_BUFFER_SIZE) ? 0 : ulReadIndex;ulLoop--;}// 完成接收所有字节并进行转换后发送给主机USBBufferDataWritten(&g_sTxBuffer, ulCount);DEBUG_PRINT("Wrote %d bytes\n", ulCount);// 返回处理的字节数return(ulCount);}// 函数void DisplayStatus// 功能：在屏幕显示当前状态的字符串// 变量psContext 指向图形上下文（context）用于OLED屏幕显示// 变量pcStatus 指向要显示字符串Void DisplayStatus(tContext *psContext, char *pcStatus){ // 清除原来状态，显示黑色背景GrContextForegroundSet(&g_sContext, ClrBlack);GrStringDrawCentered(psContext, " ", -1,GrContextDpyWidthGet(psContext) / 2, 16, true);// 显示新状态DEBUG_PRINT("%s\n", pcStatus);GrContextForegroundSet(&g_sContext, ClrWhite);GrStringDrawCentered(psContext, pcStatus, -1,GrContextDpyWidthGet(psContext) / 2, 16, true);}// 函数ui32TxHandler// 功能：处理与发送通道有关的USB设备驱动通知（数据由device向主机传送）// 变量pvCBData 是从机提供的返回指针// 变量ulEvent 正在被通知的事件// 变量ulMsgValue 是事件对应值// 变量pvMsgData is 事件指针.// 此程序被bulk驱动调用以通知USB设备（与发送数据通道有关的）事件//（IN通道将数据发送给主机）ui32TxHandler(void *pvCBData, ui32 ulEvent, ui32 ulMsgValue,void *pvMsgData){ // 此程序没有对发送事件作任何响应，只是更新发送字节数if(ulEvent == USB_EVENT_TX_COMPLETE){g_ulTxCount += ulMsgValue;}// 显示Debug信息DEBUG_PRINT("TX complete %d\n", ulMsgValue);return(0);}//函数ui32RxHandler// 功能：处理与发送通道有关的USB设备驱动通知（由主机向device发送）// 变量pvCBData 是从机提供的返回指针// 变量ulEvent 正在被通知的事件// 变量ulMsgValue 是事件对应值// 变量pvMsgData is 事件指针.// 说明：此程序被bulk驱动调用以通知USB设备（与接收数据通道有关的）事件//（OUT通道将数据由主机发送出去）ui32RxHandler(void *pvCBData, ui32 ulEvent,ui32 ulMsgValue, void *pvMsgData){ // 判断是哪一个事件状态switch(ulEvent){ // 正在与主机连接，可以进行通信case USB_EVENT_CONNECTED:{g_bUSBConfigured = true;g_pcStatus = "Host connected.";g_ulFlags |= COMMAND_STATUS_UPDATE;// 刷新缓冲区USBBufferFlush(&g_sTxBuffer);USBBufferFlush(&g_sRxBuffer);break;}// 主机断开连接case USB_EVENT_DISCONNECTED:{g_bUSBConfigured = false;g_pcStatus = "Host disconn.";g_ulFlags |= COMMAND_STATUS_UPDATE;break;}// 接收到新字节包case USB_EVENT_RX_AVAILABLE:{tUSBDBulkDevice *psDevice;// 从返回数据变量中回去实例数据的指针psDevice = (tUSBDBulkDevice *)pvCBData;// 读取新数据包并且返回发送给主机return(EchoNewDataToHost(psDevice, pvMsgData, ulMsgValue));}// 暂时忽略挂起（SUSPEND）和重启（RESUME）信号。