TI中文支持网开发板：lm4f120 launchpad
开发环境：CCS6.0.1
例程：StellarisWare 内官方例程 usb_dev_bulk
对例程基本未修改：
添加了一个全局变量x，用于x=(unsigned long)pcData; 查看pcData值
一个全局字符数组USB_READ[10] 用于USBBufferRead(&g_sRxBuffer,USB_READ,10); 读取十个字节数据
然后 我用的是自己用QT写的一个发送字符数据到设备的上位机，用的libusb—win32来完成usb端口的读写（上位机可以确认无问题）
然后我就在合适的地方设置断点，查看EchoNewDataToHost()这个函数的运行过程，然后发现没有完全按预期的运行，然后这里问几个问题：
1.ulSpace = USBBufferSpaceAvailable(&g_sTxBuffer);这句是获取发送缓存区空闲的空间，和接受缓存接收到的新数据数量有没有关系？
2.ulReadIndex = (unsigned long)(pcData – g_pucUSBRxBuffer); ulReadIndex是用于获取新接收数据在接收缓存中的起始位置（相对位置），方便从这里开始读取新数据，pcData是新数据起始的地址，然后这个pcdata是否只要有对接受缓存的读取就会移动到尚未被读取的数据处，比如USBBufferRead(&g_sRxBuffer,USB_READ,10);是否会改变pcData的值？还是说pcData在设备接收到新数据时就固定（刷新），pcData 何时赋值的，会不会因为读取操作而改变。
3.ulNumBytes是收到的总的数据，这个变量只是针对对这个例程的吗？只要接收了没被发送出去，ulNumBytes（ulMsgValue）就一直增大吗？我如果发送超过256字节（接收缓存区大小）的数据，这个例程还能正常工作吗？
4.USB_EVENT_TX_COMPLETE 这个事件在发送缓存区数据发送完毕后触发，还是发出一个数据包就触发？
5.例程是只有一条管道，极限速率能达到多少？有没有多管道的例程（如何实现多管道）？
以下是修改过的函数。
volatile unsigned long x;
volatile unsigned char USB_READ[10];
static unsigned long
EchoNewDataToHost(tUSBDBulkDevice *psDevice, unsigned char *pcData,
unsigned long ulNumBytes)
{
unsigned long ulLoop, ulSpace, ulCount;
unsigned long ulReadIndex;
unsigned long ulWriteIndex;
tUSBRingBufObject sTxRing;
//
// Get the current buffer information to allow us to write directly to
// the transmit buffer (we already have enough information from the
// parameters to access the receive buffer directly).
//
USBBufferInfoGet(&g_sTxBuffer, &sTxRing);
//
// How much space is there in the transmit buffer?
//
ulSpace = USBBufferSpaceAvailable(&g_sTxBuffer);
//
// How many characters can we process this time round?
//
ulLoop = (ulSpace < ulNumBytes) ? ulSpace : ulNumBytes;
ulCount = ulLoop;
//
// Update our receive counter.
//
g_ulRxCount += ulNumBytes;
//
// Dump a debug message.
//
DEBUG_PRINT("Received %d bytes\n", ulNumBytes);
//
// Set up to process the characters by directly accessing the USB buffers.
//
x=(unsigned long)pcData;*********************************************此处添加一行
ulReadIndex = (unsigned long)(pcData – g_pucUSBRxBuffer);
ulWriteIndex = sTxRing.ulWriteIndex;
while(ulLoop)
{
x=(unsigned long)pcData;*********************************************此处添加一行
//
// Copy from the receive buffer to the transmit buffer converting
// character case on the way.
//
//
// Is this a lower case character?
//
if((g_pucUSBRxBuffer[ulReadIndex] >= 'a') &&
(g_pucUSBRxBuffer[ulReadIndex] <= 'z'))
{
//
// Convert to upper case and write to the transmit buffer.
//
g_pucUSBTxBuffer[ulWriteIndex] =
(g_pucUSBRxBuffer[ulReadIndex] – 'a') + 'A';
}
else
{
//
// Is this an upper case character?
//
if((g_pucUSBRxBuffer[ulReadIndex] >= 'A') &&
(g_pucUSBRxBuffer[ulReadIndex] <= 'Z'))
{
//
// Convert to lower case and write to the transmit buffer.
//
g_pucUSBTxBuffer[ulWriteIndex] =
(g_pucUSBRxBuffer[ulReadIndex] – 'Z') + 'z';
}
else
{
//
// Copy the received character to the transmit buffer.
//
g_pucUSBTxBuffer[ulWriteIndex] = g_pucUSBRxBuffer[ulReadIndex];
}
}
//
// Move to the next character taking care to adjust the pointer for
// the buffer wrap if necessary.
//
ulWriteIndex++;
ulWriteIndex = (ulWriteIndex == BULK_BUFFER_SIZE) ? 0 : ulWriteIndex;
ulReadIndex++;
ulReadIndex = (ulReadIndex == BULK_BUFFER_SIZE) ? 0 : ulReadIndex;
ulLoop–;
}
//
// We've processed the data in place so now send the processed data
// back to the host.
//
USBBufferRead(&g_sRxBuffer,USB_READ,10);*********************************************此处添加一行
USBBufferDataWritten(&g_sTxBuffer, ulCount);
DEBUG_PRINT("Wrote %d bytes\n", ulCount);
//
// We processed as much data as we can directly from the receive buffer so
// we need to return the number of bytes to allow the lower layer to
// update its read pointer appropriately.
//
return(ulCount);
}
xyz549040622：
楼主暂时先放下，不用学了，LM4F系列的芯片都停产了，楼主转学TM4吧
ming zhao：
回复 xyz549040622:
额，lm4f120h5qr 貌似现在的名字叫tm4c1233h6pmi。
xyz549040622：
回复 ming zhao:
对的，是兼容系列的，但是需要修改。。。所以最好先换芯片，再玩
