Based on 51 single chip microcomputer 12864 LCD display digital function-EEWORLD

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I often check out some technical articles, and I find that many people write them in the form of blogs, saying that they are beneficial to others and themselves. I think that makes sense.

Looking back, I thought that I have applied for Sina Weibo for many years, but I rarely post blogs. So today I will post my first technical blog.

I hope I can develop this habit.

Well, it took me two hours tonight to write a simple function, probably less than 40 lines. But I did encounter some problems, but I finally solved them.

The function is to use the 12864 LCD to display numbers of any digits. Why do I write this function? Because I often use some interface functions in the process of using 12864, which is very convenient. For example, write_char(); write_string(); write character and write string functions.

But if I want to write a number, I can't do it. I can split the digits one by one and use the character display function. But this is very troublesome. The most fatal point is that since the address of 12864 is a 2-byte unit (a little unprofessional here), probably for writing Chinese characters, the numbers cannot be close together, and there will be a space in the middle, which is very wasteful. So there is this function to write numbers.

void write_num(uchar x,uchar y,unsigned long int num)

{

uchar i=10;

switch (y)

{

case 0: Lcd_WriteCmd(0x80+x);break;

case 1: Lcd_WriteCmd(0x90+x);break;

case 2: Lcd_WriteCmd(0x88+x);break;

case 3: Lcd_WriteCmd(0x98+x);break;

default: ;

}

while(i>=1)

{

if((uchar)(num/pow(10,i-1))!=0)

break;

i--;

}

while(i)

{

Lcd_WriteData(num/(u32)(pow(10,i-1))+'0');

num=num%(u32)(pow(10,i-1));

i--;

}

First of all, it is definitely not an arbitrary number of digits. After all, the display screen is so small, and the number of digits displayed must be limited. We noticed that in C language

The unsigned long int type is very large, 32 bits, 4 bytes, and the maximum value is 4294967295.

There are ten digits here, so our parameter is of type u32, and the XY parameters are the coordinate positions displayed on 12864.

The function first determines the coordinates to be written, then determines the number of digits, and then writes them one by one starting from the high digit.

Define a variable i; initialize bit 10.

It is worth mentioning that I don’t know if other people have encountered the same problem I encountered.

When using the pow function, since the library functions are defined as double type, an error will be reported when taking the remainder. I added a forced type conversion first. It didn't work, and many numbers were displayed incorrectly. After simulation debugging, I think the problem lies in the pow function.

So, I wrote the pow function myself, and used integer data types to avoid data loss during data type conversion.

After changing it like this, it will be fine.

Write the pow function I wrote, it's very simple.

u32 pow(uchar a,uchar b)

{

u32 result=1; // initialize to 1

for(;b>0;b--)

{

result*=a;

}

return result;

}

Write a calculator program in two days...

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