LCDOUT custom commands - how to?

[flotulopex]

I'm still not sure how to connect the datalines from the display to the PIC (is it DB0 = D7 and so on or is it DB0 = D4 and so on).

Here is my code:

'PIC 16F88

' LCD circuitery
'23,24,25,26,32,33,34,35,40 - Vdd (+5V)
'27,38  - Vss (GND)
'28 DB0 - PORTA.0
'29 DB1 - PORTA.1
'30 DB2 - PORTA.2
'31 DB3 - PORTA.3
'39 RS  - PORTA.4
'36 E   - PORTA.6
'37 R/W - PORTA.7


DEFINE LCD_DREG PORTA       'LCD data port 
DEFINE LCD_DBIT 4           'LCD data starting bit 0 or 4 
DEFINE LCD_RSREG PORTA      'LCD register select port 
DEFINE LCD_RSBIT 4          'LCD register select bit 
DEFINE LCD_EREG PORTA       'LCD enable port 
DEFINE LCD_EBIT 6           'LCD enable bit 
DEFINE LCD_RWREG PORTA      'LCD read/write port
DEFINE LCD_RWBIT 7          'LCD read/write bit
DEFINE LCD_BITS 4           'LCD bus size 4 or 8 
DEFINE LCD_LINES 2          'Number lines on LCD 
DEFINE LCD_COMMANDUS 2000   'Command delay time in us 
DEFINE LCD_DATAUS 50        'Data delay time in us


' Register settings
OSCCON     = %01100000      'Internal RC set to 4MHZ
ANSEL      = %00000000      'Disable Analogue Inputs
OPTION_REG = %01000000      'Enable PORTB pullups


START:
    Lcdout $FE, 1           'Clear screen


MAIN:
    pause 1000
    lcdout $FE, 2,   "This is line one"
    lcdout $FE, $C0, "This is line two"
    goto MAIN

end

[Melanie]

This...

'28 DB0 - PORTA.0
'29 DB1 - PORTA.1
'30 DB2 - PORTA.2
'31 DB3 - PORTA.3

is not compatible with this...

DEFINE LCD_DREG PORTA 'LCD data port
DEFINE LCD_DBIT 4 'LCD data starting bit 0 or 4

...and double-check with the Datasheet that you've disabled all Analogue Functions on PortA.

[flotulopex]

The display's datasheet makes me connect the lines D4 to DB3, D5 to DB2, D6 to DB1 and D7 to DB0 (see attachment "DB-Lines_connections.jpg"). This is why I thought the starting bit would be the fourth.

I changed:

DEFINE LCD_DREG PORTA       'LCD data port 
DEFINE LCD_DBIT 0           'LCD data starting bit 0 or 4

and added:

ADCON0.0   = 0              'Disable Converter Module

I went through the PIC's datasheet and couldn't find other settings that could affect the A ports. Still, the display looks just dead.

I have two of them and react the same. I changed for my second 16F88 and the result is same too.

[keithdoxey]

Normally for a 4 bit bus

DB0-DB3 = D4-D7

Also if you are using a 16F88 check the ANSEL register

[flotulopex]

ANSEL is set to have all analog ports disabled.

As you suggested, I connected DB0 to D4 and so on...

Still nothing happens.

I'm just suprised that the display don't even flickers a little. It looks just like dead. Two displays doing the same makes me think I'm doing something wrong.

Is is right to say that to make it work the Enable bit must be high? If yes, I could at least mesure it with my logic probe or oscillo....

What can I "electrically" check else to minimise the cabling error risk?

[keithdoxey]

Is there (or should there be) a contrast control that needs adjusting ?

[mister_e]

i'm not sure if PBP handle the R/W line itself.

How about LOW PORTA.7

AND maybe i'm blind.. i don't see any config fuses?

On some LCD, you need to tie the unused DB lines to GND, in your case they should be tied to 5V.

AND what about the CSB line?
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