F340 上下位机编写注意事项

最新推荐文章于 2023-07-06 06:30:00 发布

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本文详细介绍了一个USB通信程序的实现过程，包括下位机初始化、USB中断处理及上位机注意事项等关键步骤。针对上下位机USB buffersize不一致导致的问题进行了深入分析，并给出了相应的解决策略。

1. 下位机

1.1 main函数中第一步，根据需要先设置watchdog，一般不用的话，必须禁止watchdog，禁止方法见下例；

1.2 main函数第二步，设置系统时钟，具体见下例；

1.3 USB的中断函数不能省略，如省略会出现上位机不能识别USB设备的现象。

//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include "compiler_defs.h"
#include "C8051f340_defs.h"
#include <stddef.h>
#include "USB_API.h"

#define INTERRUPT_USBXpress 17

//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------



U8 Out_Packet[8] = {0,0,0,0,0,0,0,0};     // Last packet received from host
U8 In_Packet[8]  = {0,0,0,0,0,0,0,0};     // Next packet to sent to host



/*** [BEGIN] USB Descriptor Information [BEGIN] ***/
SEGMENT_VARIABLE(USB_VID, U16, SEG_CODE) = 0x10C4;
SEGMENT_VARIABLE(USB_PID, U16, SEG_CODE) = 0xEA61;
SEGMENT_VARIABLE(USB_MfrStr[], U8, SEG_CODE) = // Manufacturer String
{
   0x1A,
   0x03,
   'S',0,
   'i',0,
   'l',0,
   'i',0,
   'c',0,
   'o',0,
   'n',0,
   ' ',0,
   'L',0,
   'a',0,
   'b',0,
   's',0
};
SEGMENT_VARIABLE(USB_ProductStr[], U8, SEG_CODE) = // Product Desc. String
{
   0x10,
   0x03,
   'U',0,
   'S',0,
   'B',0,
   ' ',0,
   'A',0,
   'P',0,
   'I',0
};

SEGMENT_VARIABLE(USB_SerialStr[], U8, SEG_CODE) = // Serial Number String
{
   0x0A,
   0x03,
   'V',0,
   'S',0,
   'M',0,
   '.',0
};

SEGMENT_VARIABLE(USB_MaxPower, U8, SEG_CODE) = 15;    // Max current = 30 mA
                                                      // (15 * 2)
SEGMENT_VARIABLE(USB_PwAttributes, U8, SEG_CODE) = 0x80;    // Bus-powered,
                                                            // remote wakeup not
                                                            // supported
SEGMENT_VARIABLE(USB_bcdDevice, U16, SEG_CODE) = 0x0100;    // Device release
                                                            // number 1.00
/*** [ END ] USB Descriptor Information [ END ] ***/

SEG_CODE const U8 TEMP_ADD = 112;           // This constant is added to Temperature


//-----------------------------------------------------------------------------
// Global Constants		 (SPI)
//-----------------------------------------------------------------------------

#define SYSCLK             12000000    // Internal oscillator frequency in Hz

//-----------------------------------------------------------------------------
// Function Prototypes
//-----------------------------------------------------------------------------

void PORT_Init (void);
void T0_Wait_ms (unsigned char ms);

//-----------------------------------------
//Sepcification Port Defination
//-----------------------------------------

sbit led2 = P2^7;
sbit led3 = P2^6;

//sbit CDS = P0^4;	//P0.4 as CDS line

//-----------------------------------------------------------------------------
// Main Routine
//-----------------------------------------------------------------------------
void main(void)
{

   int i;
   PCA0MD &= ~0x40;                    // Disable the Watchdog Timer 
   PCA0MD = 0x00;	

   OSCICN = 0x83;                      // Set the internal oscillator to
                                       // 12 MHz
   PORT_Init();

   USB_Clock_Start();                  // Init USB clock *before* calling USB_Init
   USB_Init(USB_VID,USB_PID,USB_MfrStr,USB_ProductStr,USB_SerialStr,USB_MaxPower,USB_PwAttributes,USB_bcdDevice);


   USB_Int_Enable();

   OSCICN |=0x03;

   EA = 1;		//Enable all interrupt

   while (1)
   {

	  //-------------------------------------------------------------------

	  if (Out_Packet[0] == 0x01) 		 // Receive tes1 command
	  {
			
			led2 = 0;
			led3 = 0;
	  }
	  else
	  {
	  	if(Out_Packet[0] == 0x02)		// Receive test2 command
		{

			
			led2 = 1;
			led3 = 1;				  	
		}
		else
		{
			if(Out_Packet[0] == 0x03)	// Receive test3 command
			{
			 
				led2 = 1;
				led3 = 0;		  	
			}
			else
			{
				if(Out_Packet[0] == 0x04)	// Receive test4 command
				{
					
					led2 = 0;
					led3 = 1;	  	
				}
				else
				{
					if (Out_Packet[0] == 0x10) 		 // Receive read from USB command
	  				{
	    				for(i=0; i<8; i++)
						{
							In_Packet[i] = Out_Packet[i];
						}

						Block_Write(In_Packet,8);	// Send data to PC by USB

						led2=0;
						led3=1;
	  				}
					else
					P4 = 0X00;		// Led all open as default
				}	
			}
		}
	  }	  	   	
    T0_Wait_ms(1);
   }      
}

//********************************************************************
// Initialization Subroutines
//********************************************************************

void PORT_Init (void)
{
   P2MDOUT = 0xFF;                     // Make the LED push-pull
   XBR1 = 0x40;                        // Enable the XBAR and weak pull-ups
}

//********************************************************************
// USB ISR
//********************************************************************

// Example ISR for USB_API
INTERRUPT(USB_API_TEST_ISR, INTERRUPT_USBXpress)
{
   U8 INTVAL = Get_Interrupt_Source();

   if (INTVAL & RX_COMPLETE)
   {
      Block_Read(Out_Packet, 8);
   }

}


//-------------------
// T0_Wait_ms
//-------------------

void T0_Wait_ms (unsigned char ms)
{
   TCON &= ~0x30;                      // Stop Timer0; Clear TF0
   TMOD &= ~0x0f;                      // 16-bit free run mode
   TMOD |=  0x01;

   CKCON |= 0x04;                      // Timer0 counts SYSCLKs

   while (ms) {
      TR0 = 0;                         // Stop Timer0
      TH0 = -(SYSCLK/1000 >> 8);       // Overflow in 1ms
      TL0 = -(SYSCLK/1000);
      TF0 = 0;                         // Clear overflow indicator
      TR0 = 1;                         // Start Timer0
      while (!TF0);                    // Wait for overflow
      ms--;                            // Update ms counter
   }

   TR0 = 0;                            // Stop Timer0
}

2. 上位机注意事项：

2.1 使用上位机USB读写函数时，函数第二个参数的含义是，读写数据暂存的buffer指针。在参考Siliconlab实例时，其buffer是用的一个结构体，其中分别含有Input和Output，而使用实例中的读语句时，其实是将数据读到Ouput中，对编写上位机易造成困惑。

所以，最好修改实例的buffer，Input和Output统一成一个。详见下图：