:: So, How are these "static" LCDs droved?

Very similar to the way a multiplexed 7 segment LED display is driven. 
 I've driven a small 2 digit 'glass' LCD using a 74H595 and with the 
much larger ULN5832 32 bit shift register IC.

Below is the proto code written in basic not using the 5832, but the 
595.

Colin



include "MCU-CONFIG/hwreg-p16f876.h"

        pragma cpu_fosc 4000000 
  pragma cpu_heartbeat 39                        //32Hz is limit of 
LCD refresh @5v
     

hwreg tx_port = &PORTB
const COM = (1<<4)


const latch_pin =(1<<1)
const data_pin = (1<<2)
const clock_pin = (1<<3)

ubyte phase
ubyte digit




/*********************************************************************
**************
** Segment pattern depends on the shift register wiring to the LCD 
panel.
**
** 74HC595 is wired according to the following pattern.
**
** 595 Pin #'s      7  6  5  4  3  2  1  15
** 595 Outputs      Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0
**
** LCD segments     E  D  C  B  A  F  G  DP1
** LCD Pin #'s      3  4  5  14 15 16 17 2
**
**********************************************************************
*************/


const ubyte  segments = 
0b_1111_1100,0b_0011_0000,0b_1101_1010,0b_0111_1010,0b_0011_0110,
                        
0b_0110_1110,0b_1110_1110,0b_0011_1100,0b_1111_1110,0b_0111_1110,
                        0b_0111_0110        
                           

ubyte buffer

proc setup()       

  PORTB = 0
  TRISB = 0xE1
  phase = 0                        
endproc

proc ubyte get_seg(ubyte digit_seg)

ubyte  seg

     seg = segments[digit_seg]
     
     return seg
    



endproc

proc out_5832(ubyte shift_data)

        ubyte bitcount
        ubyte  phase_shift_data
        

        if (phase &1)!=0 then

                phase_shift_data = shift_data

        else

                phase_shift_data = ~shift_data
        
        endif        
        
        tx_port &= ~latch_pin
        
        
          
        for bitcount = 0x80 while bitcount >0 step bitcount>>=1 do
          
               
            tx_port &= ~ clock_pin
                 
                 
            if (phase_shift_data  & bitcount) !=0 then 
              
                  tx_port |=data_pin                
         
              else
          
                      tx_port &=~data_pin

            endif 
          
           
            tx_port |= clock_pin
            
         
        done
        
   
        tx_port = tx_port | latch_pin
        
        if (phase &1) !=0 then

           tx_port = tx_port &~COM
        
        else

           tx_port = tx_port | COM

        endif

        phase+=1
        
endproc

 
proc main()


   setup()

   digit = 0
        
   buffer = get_seg(digit)      
  
 while(1) do
  
   
    digit += 1

//test count 0->10

    if digit > 10 then
      digit = 0
    endif

    buffer = get_seg(digit)
    delay_1ms(250) 
    delay_1ms(250) 
    delay_1ms(250) 
    delay_1ms(250)  
   
  done
  
 
endproc



proc intserv()
      
                
      out_5832(buffer)

endproc





 -- 
 cdb, colin@btech-online.co.uk on 2/11/2005

 Web presence: www.btech-online.co.uk  

 Hosted by:  www.1and1.co.uk/?k_id=7988359

 We cannot become what we need to be by remaining what we are. (Max de 
Pree)



-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist