main.c

基于USB接口的GPS驱动程序.gps后段接受以及输出,及usp驱动读写

/******************************************************************
 Module description:
   Main function for all project

 Author : Yu Lu
          [e-mail]

*****************************************************************/


#include "main.h"


extern void write_usb(unsigned int usbadr, char dta);
extern void send_all_gp2021_TXD3();
extern void process_host_data(void);

extern void DELAY_1MS();

void init_clk_mem(void)
{
 ROMSIZ  |= 0X80; //  enable 1024-byte on chip XRAMs 
 PMR |= 0x01;     //  DME1:0 = 01 -> internal SRAM data memory 000-3ff
 CKCON &= 0XF8;   // clear wait state
 CKCON |= 0X02;   // wait state is 2 
 


#if M4X == 1
 /* the following code is to set the clock = 4*8Mhz */
 write_usb(0x7e01, 5);    // clock from usbn9603 = 48/(5+1) = 8 MHz
 DELAY_1MS();

 EXIF &= 0xfb;            // RGMD = 0
 PMR &= 0xef;             // clear CTM first
 PMR |= 0x08;             // 4x/2x = 1, multiplied by 4 ; CTM = 1, enable clock multiplier
 PMR |= 0x10;             // set CTM 
 while(!(EXIF & 0x08))
 {
  ;                       // wait EXIF.3 to become 1
 }
 PMR &= 0x3f;             // cd0 cd1 = 0 0
                          // after the clock freq is 4*8 = 32MHz
#endif						 
}

void main(void)
{

 init_clk_mem();
 init_ser(BAUT_115200);  // this is for 22.1184MHz  only 

#if XRAM_DBG ==1 
	init_xram();
#endif
 EA = 1;         // enable interrupt
 EX0 = 1;        // enable int0
 ES0 = 1;        // enable serial port int

 rst_usb();
 init_usb();

 start_sending = 0;

 event = 0;

  ET0 = 0;        // disable timer0 overflow int
  LPT0 = 1;       // timer0 has higher priority
  init_timer();

  status &= 0xbf; 

 while(1)
 { 
// if host send command to get data, collect data from GP2021 and send them , then clean the flag
  if( (HOST_ASK_DATA_FLAG)&&(TIME_TO_SEND_HOST) )  
   {
    send_all_gp2021_TXD3();
	CLR_HOST_ASK_DATA_FLAG;
    CLR_TIME_TO_SEND;
   } 
 } // end of while(1)

}