Pic18F452

[TonyCNC]

Hi iam am trying to use a lcd display using the picbasic pro software the display is working fine using the defult pin setup but when i change the pin configeration using the DEFINES i cant get the display to work.
can anyone help me out thanks.

[Melanie]

That's the equivallent of...

Question : "My car's broke - can you fix it?"

Answer : "Sure, bring it in and we'll take a look".

Inotherwords, post your Defines so we can see them, along with your chip register initialisation... ie if you're using analogue pins your ADCON or CMCON setup, and confirm that if you're using odd hardware pins like PortA.4, you've got a pull-up on it.

[TonyCNC]

Hi Melanie my lcd defines are:
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_DREG PORTD
DEFINE LCD_DBIT 0
DEFINE LCD_RSREG PORTE
DEFINE LCD_RSBIT 0
DEFINE LCD_EREG PORTE
DEFINE LCD_EBIT 1
DEFINE LCD_RWREG PORTE
DEFINE LCD_RWBIT 2

[MikeTamu]

If you look at the datasheet, you can see that PortE, bit 0,1, and 2 are all Analog ports. So what is most likely happening, is that the PIC is in analog mode for these pins and not giving you digital outputs.

Put this in your code before the DEFINES:

ADCON1.3=0
ADCON1.2=1
ADCON1.1=1
ADCON1.0=0

These 4 lines will make all of your analog pins into digital pins. If you need to use some of your digital pins as analog ones, then just change these 4 bits according to the table in the datasheet referenced below.

To see how I came to this, look at page 182 (184 of pdf) in the PIC 18f452 datasheet.

[TonyCNC]

Thank you very much MikeTamu i just assumed that PBP took care of all that for me as there is no reference to it in the pbp manual.

Thanks again.

[charudatt]

I am having similar problems trying to get an LCD working on EasyPIC3 from Mikroelectronika Board using PBP and 18F452 MCU. Although i can get the LED to blink , I cannot get the LCD to work. Can you help.

EasyPIC3 Development Board Configuration -
D4 - RB4
D5 - RB5
D6 - RB6
D7 - RB7
RS - RB2
E - RB3
RW - GND

My Code:

DEFINE OSC 8

' HARDWARE DEFINES
'-----------------------------------------------------------------
' Define LCD pins

DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTB
DEFINE LCD_RSBIT 2
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 3

'-----------------------------------------------------------------
TRISA = %111111 'INITIALIZE PORT DIRECTIONS
TRISB = %00000000
TRISC = %10101001
TRISD = %00000011
TRISE = %00000111
Adcon1 = 7 ' Set PORTA DIGITAL
INTCON2.7=1 ' DISABLE Pull-Up's
'-----------------------------------------------------------------
PAUSE 500

Lcdout $fe , 1 , "EasyPIC3 DEV"
LCDOut $FE,$C0, "Board v1A"
PAUSE 2000

END

[mister_e]

Be sure you set HS_OSC fuse before programming your PIC

[charudatt]

Hello,

Thanks for coming to my help once again, yes the Crystal fuse is set properly as i have a small led blink rotuine after this display , which works properly.

The LCD works with MikroBasic Compiler, But does not come on with PBP.

[paul borgmeier]

Because you are running at 8MHz, try including one or both of these and increasing the times as shown here

DEFINE LCD_COMMANDUS 4000
DEFINE LCD_DATAUS 100

[charudatt]

Hi Steve,

Your inputs in a different thread solved my problem. The code was OK just that LVP fuse was enabled.

Just disabled it and there I could see what I had to on my LCD.

Thanks.

regards

[mister_e]

GOOD!

Kind of thing to remember i guess!

[Lotondo]

If you look at the datasheet, you can see that PortE, bit 0,1, and 2 are all Analog ports. So what is most likely happening, is that the PIC is in analog mode for these pins and not giving you digital outputs.

Put this in your code before the DEFINES:

ADCON1.3=0
ADCON1.2=1
ADCON1.1=1
ADCON1.0=0

These 4 lines will make all of your analog pins into digital pins. If you need to use some of your digital pins as analog ones, then just change these 4 bits according to the table in the datasheet referenced below.

To see how I came to this, look at page 182 (184 of pdf) in the PIC 18f452 datasheet.

Thanks for the clear explanation !
As you said this will turn all 8 pins into digital.
Would it be possible to get AN0 and AN1 digital and all the others (AN2 to AN7) analog ?
It's still unclear in this case what's ADCON0 for !
Thanks for clearing me out.
Lotondo

[mister_e]

Hava a look in the datasheet, register 17-2, PDF page 184

<img SRC="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1361&stc=1&d=1170699606">

[Lotondo]

Thanks Mr E
clear enough.
I believe it's not possible to set the pins like I said :)
Could you pls. tell me something more about ADCOM0.
Datasheets are useful but something they are a little
too complicate if you are not full into the subject.
Thanks
Lotondo

[mister_e]

I can't tell anything about ADCOM As it doesn't exist, but let's try with ADCON0 ;)

If you plan to use PBP ADCIN, use my PicMultiCalc software. It make things easy. Let's say your OSC=20 MHz, your analog source impedance is 1K and you want to make a 10 Bit conversion, you need to add those DEFINEs at the top of your code


DEFINE ADC_BITS 10 ' ADCIN resolution (Bits)
DEFINE ADC_CLOCK 2 ' ADC clock source (Fosc/32)
DEFINE ADC_SAMPLEUS 3 ' ADC sampling time (uSec)

ADC_CLOCK 2 refer to ADCS1:ADCS0 bits (ADCON0<7:6>)

Sure you could even use the usual Frc and set your Sampling time to 50uSec and it will cover almost every possible situation.

Even by using the PicMultiCalc, you'll need to set the ADFM bit in ADCON1 register. Yeah i didn't include this in the software as Microchip change their mind in almost every new PIC. Maybe One day... maybe.

[mister_e]

Now, if you plan to NOT use ADCIN, you must do everything manually. Here's ashort example... OK OK it looks huge but...


'
' PIC configuration fuses
' ========================
asm
__CONFIG _CONFIG1H, _HS_OSC_1H
; HS osc (20 MHz
;
__CONFIG _CONFIG2L, _BOR_ON_2L & _BORV_27_2L & _PWRT_ON_2L
; Enable Brown out voltage detect
; Brown out voltage threshold 2.7 Volt
;
__CONFIG _CONFIG2H, _WDT_OFF_2H
; Disable watch dog timer
;
__CONFIG _CONFIG3H, _CCP2MX_OFF_3H
; Use default PORTC.1 for CCP2
;
__CONFIG _CONFIG4L, _STVR_ON_4L & _LVP_OFF_4L & _DEBUG_OFF_4L
; enable stack overflow
; disable low-voltage programming mode
; disable background debugger
;
__CONFIG _CONFIG5L, _CP0_OFF_5L & _CP1_OFF_5L & _CP2_OFF_5L & _CP3_OFF_5L
; disable code protect (user block)
;
__CONFIG _CONFIG5H, _CPB_OFF_5H & _CPD_OFF_5H
; disable code protect (boot block)
;
__CONFIG _CONFIG6L, _WRT0_OFF_6L & _WRT1_OFF_6L & _WRT2_OFF_6L & _WRT3_OFF_6L
; disable write protect (user block)
;
__CONFIG _CONFIG6H, _WRTC_OFF_6H & _WRTB_OFF_6H & _WRTD_OFF_6H
; disable Write protect CONFIG regs
; disable write protect boot block
; disable rite protect Data EE
;
__CONFIG _CONFIG7L, _EBTR0_OFF_7L
; Disable table Read protect user block
;
__CONFIG _CONFIG7H, _EBTRB_OFF_7H
; Disable Read protect boot block enable
endasm

'
' Hardware configuration
' ======================
'
DEFINE OSC 20
'
' Adc
' ---
ADCON0 = %10000001 ' Conversion clock = Fosc/32
' AN0 selected
' turn on ADC

ADCON1 = %110001110 ' right justified results
' Conversion clock = Fosc/32
' PORTA.0 as analog, all other to digital
'
' Hardware assignment
' ===================
'
' LCD
' ---
DEFINE LCD_DREG PORTD ' LCD data port
DEFINE LCD_DBIT 4 ' LCD data starting bit 0 or 4
DEFINE LCD_RSREG PORTD ' LCD register select port
DEFINE LCD_RSBIT 2 ' LCD register select bit
DEFINE LCD_EREG PORTD ' LCD enable port
DEFINE LCD_EBIT 3 ' LCD enable 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

'
' Alias definition
' ================
'
' ADC
' ---
GoDone var ADCON0.2 ' use to start/stop/check
' AD conversion

ADON VAR ADCON0.0 ' use to start/shut-off ADC

'
' Variable definition
' ===================
@AdResult = ADRESL
AdResult var word EXT ' Store ADC result

'
' Software constants
' ==================
ADC_SampleUs con 3 ' ADC sampling time

'
' Program Start here
' ==================
Pause 500 ' LCD start up delay

Start:
'
' A/D conversion
' --------------
adon = 1 ' turn on ADC
pauseus adc_sampleus ' Wait minimum sampling time
godone = 1 ' start conversion
while godone : wend ' check if finished
'
adon = 0 ' turn off ADC
'
' Show result on LCD
' ------------------
lcdout $FE,1, "Result=:", dec adresult
' show result on LCD
pause 250
goto stART

[Lotondo]

Thanks Mister_E,
your explanation is well done but it's not easy to get it into
my head (hard).
I'll try to make some practical tests.
I'll take also a look to your prg.
Regards

Lotondo

[evilpic]

Well, hi everybody ...
It seems that you all know the basics of how to manage a 2x16 LCD with the famous 18f452 but i don't ..:'(
I really need to make it work for a project, but here's my problem, i have a pic trainer with the LCD configured to work with the high nibble data bus but it has the RS-->RB2, RE-->RB3 ,R/W-->gnd, and D4-D7 -->RB4-RB7 as you see all in the same portb, i gave on trying it myself. So please could anybody give me a code to display one message on the LCD. I wouldn't mind if you have it for a 16f877 as i have that one too. I know i may be asking too much, but please help me. Thanx
just in case one of you has mercy on my soul... my email is [email protected]

[GrandPa]

Mister e, you said

"ADC_CLOCK 2 refer to ADCS1:ADCS0 bits (ADCON0<7:6>)"

I would like to know where I can find information about this. Or ,maybe easier, can you explain how ADC_CLOCK is "translated" to Focs/32. Is this simply the decimal value of ADCS1:ADCS0 bits?

Thanks!

[Melanie]

GrandPa...



"ADC_CLOCK 2 refer to ADCS1:ADCS0 bits (ADCON0<7:6>)"

I would like to know where I can find information about this


You can find the information you seek and it's all explained in great detail in the DATASHEET for the PIC you are using. Download it from www.microchip.com and study...

Tip: NEVER program a PIC without first studying it's Datasheet.

evilpic...

No, you're not asking too much, but this is very basic stuff that you should be capable of figuring for yourself.

Take a look at the LCDOUT command located here... http://www.melabs.com/resources/pbpmanual/

Scroll down until you find the DEFINE statements and change them accordingly for your preferred hardware connections.

Tip: NEVER program anything without first studying the compiler manual.

[GrandPa]

Thank's Melanie, but I've actually read the datasheet and use it currently. I'm actually setting the ADCON0 register directly instead if using the define.

My question is very specific about the DEFINE ADC_CLOCK.
What I don't understand is the meaning of the parameter (number) after the define:

In the book you have :
DEFINE ADC_CLOCK 3 'ADC clock source (rc = 3)
WHY does 3 mean RC clock ?

And

Mister e wrote:
DEFINE ADC_CLOCK 2 ' ADC clock source (Fosc/32)
Why does 2 mean Fosc/32

After reading the datasheet, I came to the conclusion that this number is the binary values of ADCS0:ADCS2 (PIC18F4620 here). But I wanted to make sure. So let me ask again:

----> Is this the decimal value of ADCS0:ADCS2 ?


(btw: I'm french, trying my best to explain my question)

J-P

[Melanie]

Yes, whatever you set in DEFINE ADC_CLOCK n, where 'n' is a number between 0 and 7 will reflect in bits ADCS2:ADCS1:ADCS0 as per the table in the PICs DATASHEET that I refered you to..

If you set a number greater than 7, then only the lowest three bits of your define will be used... ie DEFINE ADC_CLOCK 8 will set ADCS2=0,ADCS1=0 and ADCS0=0.

I will add, that if you don't specify a DEFINE ADC_CLOCK in your program, the default value if you use ADCIN will be 3 (ie ADCS2=0, ADCS1=1, ADCS0=1).

[evilpic]

I really need to comunicate a LCD serially with the computer, i'm using the windows hyperterminal to send characters through the RS232 and a MAX232 driver circuit included on my PIC trainer, this is the code i'm using to display those characters on the LCD but all i get is kinda chinese characters or nothing instead of the key i'm pressing... i guess there's something wrong with my hserin but i can't figure what exactly. i'm new to PIC so have mercy on my soul

DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 20h
DEFINE HSER_BAUD 9615
DEFINE HSER_SPBRG 25
W0 var BYTE

'Set LCD Data port
DEFINE LCD_DREG PORTB
' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_DBIT 4
' Set LCD Register Select port
DEFINE LCD_RSREG PORTB
' Set LCD Register Select bit
DEFINE LCD_RSBIT 2
' Set LCD Enable port
DEFINE LCD_EREG PORTB
' Set LCD Enable bit
DEFINE LCD_EBIT 3
' Set LCD bus size (4 or 8 bits)
DEFINE LCD_BITS 4
' Set number of lines on LCD
DEFINE LCD_LINES 2
' Set command delay time in us
DEFINE LCD_COMMANDUS 2000
' Set data delay time in us
DEFINE LCD_DATAUS 50
DEFINE HSER_CLROERR 1 'clear overflow error bit

pause 500
Lcdout $fe, 1
W0=0
again: HSERIN [ W0 ]
if W0 = 0 then again
Pause 500 ' Wait for LCD to startup
Lcdout $fe, 1 ' Clear LCD screen
Lcdout W0 ' Display W0
Pause 500 ' Wait .5 second
goto again