stm32万利的LCDdemons部分看不懂。

只看该作者 · 2008-6-19 16:14

#include "stm32f10x_lib.h"
#include "lcd.h"
u16  frame[4];    /* LCD frame buffer  */
u16  digit[4];    /* Digit frame buffer */
char text[2];

/* 'A' = 0x4E70  */

const u16 letter[26]={0x49F0,0x01F8,0x4118,0x08F8,0x4178,0x4170,0x41D8,0x09F0,0x600A,
              0x0888,0x0534,0x0118,0x0F90,0x0B94,0x4998,0x4970,0x499C,0x4974,
              0x41E8,0x6002,0x0998,0x0511,0x299A,0x0605,0x0601,0x4409};

const u16 number[10]={0x4998,0x0880,0x4878,0x48E8,0x09E0,0x41E8,0x41F8,0x4880,0x49F8,0x49E8};

const u16 arrow[2]={0x0005,0x0600}; // {Upstair,Downstair}

/*******************************************************************************
* Function Name  : convert
* Description    : converts an ascii char to the a LCD digit (previous coding)
* Input1         : char
* Input2         : point : flag indicating if a point has to be add in front of
*                  displayed character (0: no, 1: yes)
* Output         : None
* Return         : None
*******************************************************************************/
void convert (char* c,u8 point)
{
  u16 car=0,tmp;
  u8 i;
  const u16 mask[4]={0xF000,0x0F00,0x00F0,0x000F};
  const u8 shift[3]={0xC,0x8,0x4};

  if ((*c<0x5B)&(*c>0x40))  // 'A' --- 'F'
    car = letter[*c-0x41];
  else if ((*c<0x3A)&(*c>0x2F))  // '0' --- '9'
    car = number[*c-0x30];
  else if (*c==0x20) car =0;     // 'space'
  else if (*c=='+')  car = arrow[0];   // upstair
  else if (*c=='-')  car = arrow[1];   // downstair

  if (point==1) car|=0x8000;

  for (i=0;i<3;i++)
  {
    tmp = car&mask;
    digit = tmp>>shift;
  }
  digit[3] = (car&mask[3]);
}

/*******************************************************************************
* Function Name  : write char
* Description    : This function writes a char in the LCD frame buffer
* Input1         : char ascii value
* Input2         : point 0: no point to add, 1 a point to add in front of char
* Input2         : pos: position of the caracter to write [0:3]
* Output         : None
* Return         : None
*******************************************************************************/
void write_char(char* car,u8 point,u8 pos)
{
   int i;
   const u16 mask[4]={0x0F,0xF0,0xF00,0xF000};

   convert(car,point);

   if (pos == 1) for (i=0;i<4;i++) digit=(digit<<4);
   if (pos == 2) for (i=0;i<4;i++) digit=(digit<<8);
   if (pos == 3) for (i=0;i<4;i++) digit=(digit<<12);

   for (i=0;i<4;i++) frame= (frame&~mask[pos])|digit;
}

/*******************************************************************************
* Function Name  : write_string
* Description    : This function writes a string in the LCD
* Input          : string
* Output         : None
* Return         : None
*******************************************************************************/
void write_string(char* str)
{
  int i;
  for (i=0;i<4;i++) write_char(str+i,0,i);
}

/*******************************************************************************
* Function Name  : int2char
* Description    : This function convertes a 2 digit int to a char
* Input          : u8 value
* Output         : None
* Return         : None
*******************************************************************************/
char* int2char(u8 value)
{
  text[0] = 0x30 + (value/10);
  text[1] = 0x30 + (value%10);
  return(text);
}

很不解的是：假设我要输出“A”，在convert中不是已经转化得到对应letter[]中的输出码了吗？
digital[]和frame的用处在哪里？