PIC to LCD wiring problem ?

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pasanlaksiri

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Yester day i bought a 20X4 LCD and this is a schematic for LCD Alarm clock( 20X4 ).

**broken link removed**

So my prob is

That PIC to LCD wiring is not clear to me.

Plz can some one help me plzzz..
 
hi Pasan,
It would be helpful if you could post the program code, so that we can identify which pin is which.
 
hi,

The port pin references from the posted site shows this:

Code: 
-- pin assignment for the 4-bit (6 PIC I/O pins) interface:
--
-- PIC        HD44870
-- ----------------------
--  5 Gnd      1 Gnd
-- 14 Vcc      2 Vcc
--  5 Gnd      3 Contrast 
--  6 B0      11 D4
--  7 B1      12 D5
--  8 B2      13 D6
--  9 B3      14 D7
-- 10 B4       4 RS D/I_
--  5 Gnd      5 R/W_
-- 11 B5       6 E
--
-- pin assignment for the 8-bit (11 PIC I/O pins) interface:
--
-- PIC        HD44870
-- ----------------------
--  5 Gnd      1 Gnd
-- 14 Vcc      2 Vcc
--  5 Gnd      3 Contrast
-- 17 A0       4 RS D/I_
--  5 Gnd      5 R/W_
--  1 A1       6 E
--  6 B0       7 D1
--  7 B1       8 D2
--  8 B2       9 D3
--  9 B3      10 D4 
--  6 B4      11 D4
--  7 B4      12 D5
--  8 B6      13 D6   (2k2 series resistor for ISP!)
--  9 B7      14 D7   (2k2 series resistor for ISP!)
--

It dosn't seem to make much sense when compared to the circuit.

I'm assuming the 8 bit LCD 16F877 connect list.

Where is the RS line, it says PORTA.1 in the list, also the LCD contrast is grounded??
 
pasanlaksiri said:
es it is
Click to expand...

hi Pasan
Have you compared the table I posted [taken from that website] with your circuit diagram?

It does not match.
 
ericgibbs said:
hi Pasan
Have you compared the table I posted [taken from that website] with your circuit diagram?

It does not match.
Click to expand...

Ya it doesn't match. But i can take sme idea from it.

Thanks
 
pasanlaksiri said:
Ya it doesn't match. But i can take sme idea from it.

Thanks
Click to expand...

I would consider using your compiler/assembler to produce the *.hex code from the JAL files,
then using a dis-assembler to get a 'normal' source code listing.

IIRC WinPicPro [Nigel has referred to at time?], no sure, never used a PIC dis''

This should enable you to decide which PIC pins drive which LCD pins.
Also use a 10K pot on the LCD Vo Contrast.
 

I think he set that display to MAX Contra.

Thanks for the advice. I'll use Preset
 
pasanlaksiri said:
I think he set that display to MAX Contra.

Thanks for the advice. I'll use Preset
Click to expand...

Yes, use the preset - on many LCD's setting it to maximum means it doesn't work (it just gives all black squares).
 
Nigel Goodwin said:
Yes, use the preset - on many LCD's setting it to maximum means it doesn't work (it just gives all black squares).
Click to expand...

Yes, I also have 16X2 LCD connected to the PC. When i ground that pin Its shows only black squares
 
I have a serious problem again about Programing the PIC.

When im trying to Program ( main.hex ) the PIC its always faill to verify. My programmer is also working properly.

I set configurations as he said so.

osc hs
watchdog off
powerup on
protection off

But all ways get same error.
Then I and select XT osc. Then its verify the chip. But it doesn't work.

Y really it wont verify the chip? Is it coz of problem in the source codes

Here is the files
**broken link removed**

**broken link removed**

Thanks guys
 
What error do you get? It fails to verify? What type of programmer are you using?

Also use the mangage attachments instead of some bizzare remote site, just zip them and post here.

PS I downloaded you .asm file, what did you edit it with? It's unreadable.

PPS all black squares on an LCD might mean too high a contrast, you should put the 20K pot on the design, usually one line of dark (not black) squares on a 2x16 LCD is about right. Both you'll never see anything. It varies from LCD to LCD and temperature.
 
Last edited:
blueroomelectronics said:
What error do you get? It fails to verify? What type of programmer are you using?

Also use the mangage attachments instead of some bizzare remote site, just zip them and post here.
Click to expand...

Also use the mangage attachments instead of some bizzare remote site
Click to expand...

I hv never been use that b4. Thats y i fogot that. Sorry

What error do you get? It fails to verify? What type of programmer are you using?
Click to expand...

Yes its fail to verify,

My programmer is Multi PIC Programmer 5v2.

I programm same PIC using that programmer perfectly
 

Attachments

  • LCDClock.zip
    27.9 KB · Views: 114
hi,

Like Bill found, it will not assemble. its full of worms, where did you get it from?
 
pasanlaksiri said:
https://www.thouters.be/PicAlarmClock

Hmmmm **** I waist my time on this.
Click to expand...

Please hold patience

please send a detail of what pins you have connected for the 10 wire cable clearly indicating cross connections of the pin numbers of 16 pin LCD display .

let us see, afterall the site gave so many photos to make me atleast feel that genuine effort was there.
Take little more pains
 
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