Mr Robert
Here is some code I used for a 4X40 display (the reason for E1 and E2). It may give you an idea how to send data to the LCD from the PC. I assume you have a program that can be written to send and receive data via the serial port in your PC.
Code:
' PicBasic program to demonstrate operation of an LCD in 4-bit mode
' LCD DMC40457 W/backlight 16F876
' LCD should be connected as follows:
' PIN--LCD PIC 4016
' 4 DB4 PortB.4
' 3 DB5 PortB.5
' 2 DB6 PortB.6
' 1 DB7 PortB.7
' 11 RS PortB.0
' E PortB.1 pin 8 & 11
' 10 RW Ground
' 14 Vdd 5 volts
' 13 Vss Ground
' 12 Vo 10K potentiometer (or ground)
' DB0-3 No connect
' 9 E1 To enable logic ckt pin 9
' 15 E2 as above pin 10
'Backlight controled via a NPN transistor with 1K resistor from porta.2 to base.
' E1 & E2 controlled via a bilaterial switch 4016
' portc.4 pin 6
' portc.5 pin 12
'*********************************************************************************
DEFINE LOADER_UESD 1 'Enable bootloader
DEFINE OSC 20 ' 20Mhz Xtl
DEFINE HSER_RCSTA 90h 'Set up USART
DEFINE HSER_TXSTA 24h
DEFINE HSER_BAUD 9600
DEFINE LCD_DREG PORTB 'Set up LCD Data Portb
DEFINE LCD_DBIT 4 ' bit 4 - 8 data bus
DEFINE LCD_RSREG PORTB 'RS portb.0
DEFINE LCD_RSBIT 0
DEFINE LCD_EREG PORTB 'E portb.1
DEFINE LCD_EBIT 1
DEFINE LCD_BITS 4 '4 data bits
DEFINE LCD_LINES 2 '2 lines
DEFINE LCD_COMMANDUS 2000
DEFINE LCD_DATAUS 50
ADCON1 = 7 'Make porta all digital
trisa = %00000000 'Make porta all outputs
output portc.4 ' E1 to 4016
output portc.5 ' E2 to 4016
RCIF VAR PIR1.5 ' Alias RCIF (USART Receive Interrupt Flag)
OERR VAR RCSTA.1 ' Alias OERR (USART Overrun Error Flag)
CREN VAR RCSTA.4 ' Alias CREN (USART Continuous Receive Enable)
buffer_size CON 32 ' Sets the size of the ring buffer
buffer VAR BYTE[buffer_size] ' Array variable for holding received characters
index_in VAR BYTE ' Pointer - next empty location in buffer
index_out VAR BYTE ' Pointer - location of oldest character in buffer
bufchar VAR BYTE ' Stores the character retrieved from the buffer
bufchar1 VAR BYTE
i VAR BYTE ' loop counter
col VAR BYTE ' Stores location on LCD for text wrapping
errflag VAR BYTE ' Holds error flags
A VAR BYTE
E1 VAR portc.4 'E1 control to 4016
E2 VAR portc.5 'E2 control to 4016
index_in = 0 'Initalize varialbles
index_out = 0
i = 0
col = 1
low porta.2 'turn off backlight
errflag = 0 ' Reset the error flag
INTCON = %11000000 ' Enable interrupts
On INTERRUPT GoTo serialin ' Declare interrupt handler routine
PIE1 .5 = 1 ' Enable interrupt on USART
high E1 ' Enable E1
High E2 ' Enable E2
Pause 500 ' Wait for LCD to startup
START:
GOSUB OPENING 'Staart lcd display indication
Lcdout $fe, 1 'clear LCD
low E2 ' Disable E2 turn off second half of display
GOTO LOOP
LOOP:
display: ' dump the buffer to the LCD
IF errflag Then error ' Handle error if needed
If index_in = index_out Then Loop ' loop if nothing in buffer
GoSub getbuf ' Get a character from buffer
'IF bufchar = 253 THEN CONT 'if control character is detected go to control
LCDOut bufchar ' Send the character to LCD
GoTo display ' Check for more characters in buffer
' Subroutines
Disable ' Don't check for interrupts in this section
getbuf: ' move the next character in buffer to bufchar
index_out = (index_out + 1) ' Increment index_out pointer (0 to 63)
If index_out > (buffer_size - 1) Then index_out = 0 ' Reset pointer if outside of buffer
bufchar = buffer[index_out] ' Read buffer location
IF bufchar = 253 THEN CONT 'if control character is detected go to control
Return
error: ' Display error message if buffer has overrun
IF errflag.1 Then ' Determine the error
LCDOut $FE,$c0,"Buffer Overrun" ' Display buffer error on line-2
Else
LCDOut $FE,$c0,"USART Overrun" ' Display usart error on line-2
EndIf
LCDOut $fe,2 ' Send the LCD cursor back to line-1 home
For i = 2 To col ' Loop for each column beyond 1
LCDOut $fe,$14 ' Move the cursor right to the right column
Next i
errflag = 0 ' Reset the error flag
CREN = 0 ' Disable continuous receive to clear overrun flag
CREN = 1 ' Enable continuous receive
GoTo display ' Carry on
' Interrupt handler
serialin: ' Buffer the character received
If OERR Then usart_error ' Check for USART errors
index_in = (index_in + 1) ' Increment index_in pointer (0 to 63)
If index_in > (buffer_size - 1) Then index_in = 0 'Reset pointer if outside of buffer
If index_in = index_out Then buffer_error ' Check for buffer overrun
HSerin [buffer[index_in]] ' Read USART and store character to next empty location
If RCIF Then serialin ' Check for another character while we're here
Resume ' Return to program
buffer_error:
errflag.1 = 1 ' Set the error flag for software
' Move pointer back to avoid corrupting the buffer. MIN insures that it ends up within the buffer.
index_in = (index_in - 1) MIN (buffer_size - 1)
HSerin [buffer[index_in]] ' Overwrite the last character stored (resets the interrupt flag)
usart_error:
errflag.0 = 1 ' Set the error flag for hardware
Resume ' Return to program
cont:
index_out = (index_out + 1) ' Increment index_out pointer (0 to 63)
If index_out > (buffer_size - 1) Then index_out = 0 ' Reset pointer if outside of buffer
bufchar = buffer[index_out] ' Read buffer location
if bufchar = "A" then E1_ ' enable 1st half of display
if bufchar = "C" then E2_ 'enable 2nd half of display
if bufchar = "B" then BL_On 'backlight on
if bufchar = "F" then BL_Off 'backlight off
goto display
E1_:
high E1
Low E2
PAUSE 50
Lcdout $fe, 2
goto display
E2_
low E1
High E2
Pause 50
Lcdout $fe, 2
goto display
BL_On:
high porta.2
goto display
BL_Off:
low porta.2
goto display
OPENING:
FOR A = 1 TO 2
Lcdout $fe, 1 ' Clear LCD screen
Lcdout "LCD" ' Display Hello
Pause 500 ' Wait .5 second
'enable debug
Lcdout $fe, 1 ' Clear LCD screen
Lcdout $FE, $C0
Lcdout "ACTIVE"
Pause 500 ' Wait .5 second
'enable debug
NEXT A
RETURN
end
Need idea hove to..?
Originally Posted by phoenix_1
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