Index of sample code pages

This page is more of an idea than a finished product, we need help to fill it out.

These are short sections of code for particular tasks. The first goal is to get code that works. Later goals include:

• Easily modified code..
• Robust: failure resistant even with bad input.
• Fast
• Plays well when imbeded with other routines.
• Minimum resource use.

Because of the different goals we may have more than one sample in each category.

The perfect second

Timing routines, showing how seconds can be counted. Want high accuracy even with odd clock rates.

Output to A Shift Register

Often used for port expansion.

This seems to work for 8 bits to a 74HC/HCT164

    void shiftOutByte( unsigned char aData ) {
    
    	unsigned char ix;
    
    	for( ix = 0; ix < 7; ix++ )   {
    	
    		if ( aData.1 ) {
    			set_bit( SRPort, SRDataBit );
    		} else {
         		clear_bit( SRPort, SRDataBit );
    		}
    		
    		clear_bit( SRPort, SRClockBit );   // edge triggered low to high 
    		aData  >>= 1; // put here as delay 
    		set_bit( SRPort, SRClockBit );
    	
       }
    	return;

    }

Software Circular Buffer

A place to store and retrieve data, say bytes. First in First out. Methods to add and remove data. Code still needed.

read before write

Solving the issue of PIC16's pin state not being saved internally. Code still needed.

Good Main Program Header

A C Program Header Example A good header is a help to anyone who wants to use your code.

Counting Down with Unsigned Numbers

You are counting down and want to know when an unsigned number goes negative ( never ). You could declare it signed, slowing everything down. Instead check against FF. This assumes you do not use FF on the positive side. It also assumes you are counting down by one, else you could skip over FF.

  if ( 0xFF == ix ) ..

Access Bytes Inside Another Type

Example use a union:

    typedef union {
         unsigned int ui;
         unsigned char b[2];
    } noportable_int;
    
    //main program starts here.    
    void main()   {
    
         noportable_int n;
    
         n.ui        = 0x1234;
    
         n.b[0]      = tmr1l;
         n.b[1]      = tmr1h;
    
    }

idea from: [1]