Serial LCD problem

[Bruce]

Sorry to butt-in here, but I noticed a few things that might cause you problems.

Change OSCCON = %01101110 to OSCCON = %01101100. This jives with your particular oscillator configuration.

You're writing to SSPCON configuring it for "SPI Master", but you're not using this hardware with shiftin/shiftout. Don't setup SPI hardware if you don't use it. This affects RB1, RB2, and RB4.

[mind]

Hi Bruce

I was originally using SEROUT, but then it was pointed out that for SPI mode, I should be using SHIFTOUT. I have since corrected it, and resposted the code.

Later, I will attach a A/D on the SPI bus, so it is important to get these things right !

Best regards
Richard

[NavMicroSystems]

Richard,

Bruce is absolutely right regarding the OSCCON and SSPCON settings.

The latest code you have posted still contains incorrect values.

(I had mentioned OSCCON earlier)

I'm not sure if writing to SSPCON would have any negative effect, but as you are not using the MSSP module it doesn't help either, so just remove that line.

To help any further I would have to have a closer look to the datasheet.
(I will when I find time to)

P.S.
There is one more thing you could try:

run some loops that set "contrast" and "bias" vlaues from $00 to $FF

at some point "black boxes" should appear on the LCD.

[mind]

Hi Ralph

Checking the forums before sleep huh ? Heheh

Good suggestions about running loops. Will add fixes, and try it out, and see.

I still think it is something stupid I am missing ......

Best regards
Richard

[G8RPI]

Hi,
I hate to butt into a long thread - but,
This module will also work in the "normal" 4 or 8 bit parallel mode, why don't you try usinging it in 4 bit parallel mode with the standard LCDOUT command?
This would prove that the basic display is working OK. SPI is like RS232 in that it's a standard with many variables. It's not the best choice for your first project, especially with a device that has not been used with PBP before (as far as we know).

HTH Robert.

[mind]

Hi guys

Okay, so I hooked up the display in 4bit mode, and it works fine.

Unfortunately, I need to use it with a SPI connection which will be shared with an A/D. Going to a bigger device is not an option for various reasons.

So, if I want to be using SPI, should I be using SEROUT, or SHIFTOUT ?

I basically have 3 pins on the LCD. SerialIn, Clock, and RegisterSelect (we can hold ChipSelect low, since the LCD is the only SPI device on the breadboard at the moment). How hard can it really be ? Its meant to be BASIC !

Best regards
Richard

[mind]

Hi guys

Solved the problem. It really is simple, once you look at it. Did this with a PIC16F88, and a Electronic Assembly EA-DOGM162 LCD in serial connection.

Since I hate reading old posts where the person has the same problem as I did, and solved it, but there is no mention of the solution, I have included working code below.

    DEFINE OSC 4
    DEFINE CHAR_PACING 1000  
@   DEVICE  PIC16F88, INTRC_OSC_CLKOUT, WDT_OFF, PWRT_ON, BOD_OFF, MCLR_OFF, PROTECT_OFF
    disable interrupt

    osccon = %01101100
    trisb  = %00000000
         
    LCD_RS_CommandLow VAR portb.1
    LCD_SerialIn VAR portb.2
    LCD_Clock VAR portb.4

    SYMBOL mode = 5
          
    pause 40   ' wait for LCD to startup
    shiftout LCD_SerialIn, LCD_Clock, mode, [$38]
    pauseus 30
    shiftout LCD_SerialIn, LCD_Clock, mode, [$39]
    pauseus 30
    shiftout LCD_SerialIn, LCD_Clock, mode, [$14]
    pauseus 30
    shiftout LCD_SerialIn, LCD_Clock, mode, [$78]
    pauseus 30
    shiftout LCD_SerialIn, LCD_Clock, mode, [$5E]
    pauseus 30
    shiftout LCD_SerialIn, LCD_Clock, mode, [$6A]
    pause 200
    shiftout LCD_SerialIn, LCD_Clock, mode, [$0C]
    pauseus 30
    shiftout LCD_SerialIn, LCD_Clock, mode, [$01]
    pause 2
    shiftout LCD_SerialIn, LCD_Clock, mode, [$06]
    pauseus 30
    
    high LCD_RS_CommandLow
    pauseus 2
    shiftout LCD_SerialIn, LCD_Clock, mode, ["Hello world"]
    end

Best regards
Richard