A little 'Techie' help please

L

Lez T

Member
Russ, thanks but yes I am using output 7 on the 18x, you have no idea how many times I have checked that out. Latest board shows me 'blocked characters' where the welcome message should be (see pic).
When using n2400 I get the data led flashing on from off.
When using t2400 I get the data led flashing off from on.
I have tried 1200 baud rate from the 18x no difference.
I have tried 9600 baud rate on the FRM010 no difference.
One thing I read in the controller chip for the screen data sheet was
· Interfacing to a 4-bit MPU
The HD44780U can be connected to the I/O port of a 4-bit MPU. If the I/O port has enough bits, 8-bit
data can be transferred. Otherwise, one data transfer must be made in two operations for 4-bit data. In
this case, the timing sequence becomes somewhat complex. (See Figure 17.)
See Figure 18 for an interface example to the HMCS4019R.
Note that two cycles are needed for the busy flag check as well as for the data transfer. The 4-bit
operation is selected by the program.
Click to expand...
This is on p33 of the datasheet here, I don't know if this is 'standard' procedure for 4 bit control.
Attached is a picture of my 'vero' breadboard layout, black circles on holes indicate that the track is cut. At first the LCD looks as if it is connected incorrectly but pin 1 is connected to the link wire to ground. The LCD is on a header which makes it appear wrong.
Thanks to everyone who has assisted so far.
Regards.
Lez.:)
Sorry about the size of the picture but I thought that bigger was better in this case, ( technique is rumoured to be a good start too !!!) so I'm told, often!
 
Last edited:
L

Lez T

Member
Just added a header to the original LCD from the AXE033 and it gives the same display as the 'new' ones I have, just 'bked out' characters where the welcome message should be.
Regards.
Lez.
I am also waiting for some more AXE033 firware chips to arrive as I 'let out the smokelets' on the original one, can't see it's problem I've reversed into the garage intead of driving in, car still worked when it was in the wrong way round.......! ;)
 
R

russbow

Senior Member
Lez, thanks details, will ring IDC.

If it means anything, I have never seen a welcome message.

Don't want to go down the 8 bit path, stay with the serial chip, 3 lines in and 7 from chip to display.
 
hippy

hippy

Ex-Staff (retired)
From the picture everything looks right. The resonator seems a long way from the chip which could present problems but if the LED is flashing as data is sent it suggests it's running code though possibly not at the right speed. Though even running slow it should still initialise the LCD okay and clear the black blobs.

I cannot see how the top +V and 0V tracks connect to the bottom +V and 0V tracks.

With JP3 ( leg 7 ) to 0V the SEROUT should be N2400. I couldn't see the 0V connection to the sending PICAXE.

The list of possible things wrong I can think of then becomes -

1) Shorts on reverse of board
2) Resonator too far away
3) Power not 5V, or power not connected right
4) No 0V connection to sending PICAXE
5) Sending unsupported commands to FRM010
6) FRM010 is damaged
 
L

Lez T

Member
@H,
Top and bottom power rails are connected under the LCD.
Power running @5.07v
Resonator only moved away for clarity of image on the original board it was about 5 -7 mm
0v connection via AXE091 pin10 below pin 9 on 18x socket
Been over the back of the board with a magnifying glass to check it.
Code to FRM010
Code: 
main:
pause 500
serout 7,n2400,(254,1)     'clear screen
pause 50
serout 7,n2400,(254,1)     'clear screen
pause 100  
serout 7,n2400,(254,128,"line one")      'print line one
pause 1000
serout 7,n2400,(254,192,"line two")      'print line two
pause 2000
goto main
FRM010 new out of tube from REV-ED Thursday. LCD fresh out of the packet too.

Is it standard for 4 bit commands to be sent twice to work on a 4 or 8 bit LCD? see datasheet P33
· Interfacing to a 4-bit MPU
The HD44780U can be connected to the I/O port of a 4-bit MPU. If the I/O port has enough bits, 8-bit
data can be transferred. Otherwise, one data transfer must be made in two operations for 4-bit data. In
this case, the timing sequence becomes somewhat complex. (See Figure 17.)
See Figure 18 for an interface example to the HMCS4019R.
Note that two cycles are needed for the busy flag check as well as for the data transfer. The 4-bit
operation is selected by the program.
Click to expand...
Regards.
Lez.
 
E

eclectic

Moderator
@Lez.
I've just tried your program from post #47.

AXE091 board. 18X
Three separate FRM010 chips and Veroboards.
Three LCD modules. 2 x 20, 4 x 20, 2 x 40

Absolutely fine.

Then,
Code: 
#picaxe 18X

main:
serout 7,n2400,(254,1)     'clear screen
pause 50
 
serout 7,n2400,(254,128,"line one")      'print line one
pause 1000
serout 7,n2400,(254,192,"line two")      'print line two
pause 2000
goto main
Again, it all works fine

Now, I'm absolutely perfect and I've never made a solderng error :)

But, just in case you have,

1 Follow the advice in previous posts.
2 Get that magnifying glass out again!
3. Get a blade / fine point and clean the Veroboard insulation tracks

e
 
Last edited:
L

Lez T

Member
Solution found, well, it's working and I don't know why..

:D: :D
To all out there who have put up with me for the last week regarding these LCD's thank you.
For some strange reason known only to a higher being (**ppy), the LCD/ FRM010 has decided to work, at the moment it will not save messages in its memory. I don't care about that, ITS WORKING!!!!
Thank you all for your help.
Best Regards.
Lez.
PS are the messages stored in the LCD or the FRM010 ? Ta..
:D: :D
 
W

westaust55

Moderator
Lez T said:
:D: :D
To all out there who have put up with me for the last week regarding these LCD's thank you.
For some strange reason known only to a higher being (**ppy), the LCD/ FRM010 has decided to work, at the moment it will not save messages in its memory. I don't care about that, ITS WORKING!!!!
Thank you all for your help.
Best Regards.
Lez.
PS are the messages stored in the LCD or the FRM010 ? Ta..
:D: :D
Click to expand...
Great to read that it is working.

But question remains what is/was wrong?

Did you move it about? If so, check for bad (cold) solder joints or even a broken wire even within insulation.


Going back to your test program, you should be able to remove one of the screen clear commands:
Code: 
main:
pause 500
serout 7,n2400,(254,1)     'clear screen
pause 100  
serout 7,n2400,(254,128,"line one")      'print line one
pause 1000
serout 7,n2400,(254,192,"line two")      'print line two
pause 2000
goto main
If you find that it is operating intermittently, one possibility is a slow rise time for the power supply on switch on - can be caused by too much capacitance on the power supply.
In this case, try adding a reset commands from the PICAXE via the FRM010 to the LCD.
 
L

Lez T

Member
@AC,
Thank's, I didn't know which it was.

@Westy,
I wish I knew what had been wrong, I removed the LCD ( it's on a header ), removed the FRM010 ( from its socket ), I went through all the posts in this thread, and @Russ's link to a previous thread, just in case there was something there that I'd missed. I then rechecked the soldering and the tracks on the board, cleaning every groove there was, even though I couldn't see anything wrong. I made the board so it must have been there even though I couldn't see it.
My non saving of messages and the occasional odd character that I am getting now is probably down to the resonator being so far away from the chip,as @Hippy pointed out a few posts ago, I spread everything out so the board was easy to 'read'.

Thank you all again for your time and patience, this forum is the best tool I have ever had for my toolbox.
I raise my hat to you all.
Lez.
 
Last edited:
P

Pfrogs

Member
Hi Lez,

Glad to see u sort it out and got it to work.
It could have well been the cleaning that solved the problem. I've had issues before that were "magically" solved by cleaning the "invisible" bridges :D
Good luck with the rest of your Picaxe project!
 
D

Dippy

Moderator
Good to see you have sorted it.
Dodgy wiring/connections are annoyingly common causes of faults.
... as are breaks in single-core link wires on breadboards.
It can drive you mad.
 
R

russbow

Senior Member
Well done Lez.

Now...........try each of your FRM chips one by one and put any that dont work in a potential 'binit' box.

....................then do the same for you LCDs.

Bet you find more work than you expected - except the one you reversed in!

Russ
 
hippy

hippy

Ex-Staff (retired)
cleaning every groove there was, even though I couldn't see anything wrong.

That's probably it in my experience. Always a good idea I've found to run a craft knife between the copper strips. Also check that track cuts are clean and don't have a sliver of track still linking them. I find it's sometimes easy to forget to cut the tracks under an IC !
 
You must log in or register to reply here.
Top