LCD Serial Display

jc173 · Apr 29, 2009

I've got a PCB, soldered on 3 flying wires going to the Serial LCD and used the following BASIC syntax as a test

Code:

main:
          serout 7, N2400, ("Test 1 2 3")
          goto main

When everything is switched on it is not working at all.

I have run test codes to check the other in/output devices work and they all do, i've replaced the screen with another screen....

any ideas?

TIA

James

eclectic · Apr 29, 2009

@James.

Have a look at

http://www.rev-ed.co.uk/docs/axe033.pdf

especially page 8 onwards,
for some further information.

e

westaust55 · Apr 30, 2009

James,
try adding an extra line

PAUSE 500

at the start before the SEROUT command.
Can try longer than 500 if you want

That will give the display time to initialise.
Next step would be to send a reset command to the LCD (read the LCD manual to find out how to do that)

Just to make sure you are on the right track:
which PICAXE chip are you using?
Which physical pin is the LCD connected to?

Technical · Apr 30, 2009

If you get nothing at all on the screen don't forget the contrast adjustment!

jc173 · Apr 30, 2009

Technical said:
If you get nothing at all on the screen don't forget the contrast adjustment!

Thanks for that, have been playing with that to ensure it's right

westaust55 said:
James,
try adding an extra line

PAUSE 500
at the start before the SEROUT command.
Can try longer than 500 if you want

That will give the display time to initialise.
Next step would be to send a reset command to the LCD (read the LCD manual to find out how to do that)

Just to make sure you are on the right track:
which PICAXE chip are you using?
Which physical pin is the LCD connected to?

ok, pause 500 will try that

Micro controller is a PICAXE 18A
it's on physical pin 13 which is I/Put 7

eclectic · Apr 30, 2009

@James.
I don't have an 18A, so I used an 18X

AXE091 board / AXE033 LCD
Power = 4 x NiMh AA ~ 4.97v

The following four programs all work, producing screen output.

Code:

main:
          serout 7, N2400, ("Test 1 2 3")
          pause 1000
          goto main
          
################          
  main:  
  serout 7, N2400, ("Test 1 2 3")
          pause 1000
          goto main
          
#################          
  
  serout 7, N2400, ("Test 1 2 3 *")
          pause 1000
          goto main
  
##################  

serout 7,n2400,(254,1)
pause 50
main:
 serout 7, N2400, ("Test 1 2 3")
          pause 1000
          goto main

I then changed power supply to three slightly used AA (~ 4.4v)
= NO display.

Please check your PCB wiring and your power supply.

The AXE033 needs ~ 5.0 v.

e

jc173 · Apr 30, 2009

eclectic said:
@James.
I don't have an 18A, so I used an 18X

AXE091 board / AXE033 LCD
Power = 4 x NiMh AA ~ 4.97v

The following four programs all work, producing screen output.

Code:

main: serout 7, N2400, ("Test 1 2 3") pause 1000 goto main ################ main: serout 7, N2400, ("Test 1 2 3") pause 1000 goto main ################# serout 7, N2400, ("Test 1 2 3 *") pause 1000 goto main ################## serout 7,n2400,(254,1) pause 50 main: serout 7, N2400, ("Test 1 2 3") pause 1000 goto main

I then changed power supply to three slightly used AA (~ 4.4v)
= NO display.

Please check your PCB wiring and your power supply.

The AXE033 needs ~ 5.0 v.

e

Power Supply is a 6.0v AC --> Adaptor

eclectic · Apr 30, 2009

"Power Supply is a 6.0v AC --> Adaptor"

Sorry. Could you explain further please?

e

jc173 · Apr 30, 2009

eclectic said:
"Power Supply is a 6.0v AC --> Adaptor"

Sorry. Could you explain further please?

e

The device is mains operated so it uses a plug in 6.0V transformer to convert back from 230v AC to 6.0v DC output

eclectic · Apr 30, 2009

"The device is mains operated so it uses a plug in 6.0V transformer to convert back from 230v AC to 6.0v DC output"

6 VOLTs? For the Picaxe and the LCD?

Oh Dear..........

e

jc173 · Apr 30, 2009

eclectic said:
"The device is mains operated so it uses a plug in 6.0V transformer to convert back from 230v AC to 6.0v DC output"

6 VOLTs? For the Picaxe and the LCD?

Oh.

e

Yes 6v supply for the whole circuit...basically a 4 cell battery pack effect....

eclectic · Apr 30, 2009

"Yes 6v supply for the whole circuit...basically a 4 cell battery pack effect...."

What IS your power supply?
Unregulated / regulated/ ...........

6 volts sounds extreme for an LCD display. :-(

e

jc173 · Apr 30, 2009

eclectic said:
"Yes 6v supply for the whole circuit...basically a 4 cell battery pack effect...."

What IS your power supply?
Unregulated / regulated/ ...........

6 volts sounds extreme for an LCD display. :-(

e

It's a AC Plug in Power Supply Unit (Output 6v), unsure if it's regulated or unregulated...i'd guess at unregulated

BeanieBots · Apr 30, 2009

In which case, unloaded (or with just a PICAXE and LCD) it likely to be close to 9v. Enough to destroy both PICAXE and LCD.

STRONGLY suggest the use of batteries or a quality REGULATED 5v supply.

boriz · May 1, 2009

Do you have a multimeter? Can you measure the unloaded output of this '6v' supply?

jc173 · May 1, 2009

boriz said:
Do you have a multimeter? Can you measure the unloaded output of this '6v' supply?

it is just under 6 volts, at about 5.7...

westaust55 · May 1, 2009

eclectic said:
@James.

The AXE033 needs ~ 5.0 v.

e

The AXE033 has a link that can be fitted to permit operation for a 4.5V supply (eg 3 x AA batteries). I use a header and bridge link than can be removed or fitted as necessary.

Unfortunately many Rev Ed datasheets DO reference 6Vdc as the supply.

jc173 · May 1, 2009

I think i've found my problem, We currenty have 3 pins connected:

V+
V-
and on output pin 7 (Physical 13)

Is there a requirement to have an input pin connected two, meaning 4 pins??

Technical · May 1, 2009

No input pin required. Are you connecting to output 7 directly (correct) or to the darlington driver output on a project board like the CHI030 (incorrect) ?

boriz · May 1, 2009

"it is just under 6 volts, at about 5.7"

Assuming that’s a DC reading on a DC transformer...

If that's the unloaded reading for an unregulated 6v transformer then throw it away, it's probably broke.

If that's the reading for a regulated 6v transformer, then it's fairly close to spec, and if it stays close to the same level when loaded, then it's probably working fine. But throw it away anyway because it's useless for a Picaxe. (Or you can use a series silicon rectifier diode to drop .7v but that’s really just a botch solution and not good practice for a finished project)

Use an unregulated 9v transformer and a 7805 5v regulator. I think that’s what most people do. Should work fine if you haven’t already fried something.

jc173 · May 1, 2009

Technical said:
No input pin required. Are you connecting to output 7 directly (correct) or to the darlington driver output on a project board like the CHI030 (incorrect) ?

Directly connecting and then using a 3 pin connector onto the Pin on the LCD

westaust55 · May 2, 2009

JC173,

exactly which serial LCD module are you using?

If it is the AXE033 you would have to have assembled it.

Many here are assuming the AXE033 but is it from another vendor (eg Peter Anderson)?

which board do you have the PICAXE chip on? a Rev Ed protoboard or breadboard.

Can you upload a photo of your arranagement - clear enoght so that we can see each wire and a circuit schematic diagram (or sketch) would be helpful.

jc173 · May 2, 2009

westaust55 said:
JC173,

exactly which serial LCD module are you using?
If it is the AXE033 you would have to have assembled it.

AXE033 is what I'm using

which board do you have the PICAXE chip on? a Rev Ed protoboard or breadboard.

It's a PCB etched at school.

Can you upload a photo of your arranagement - clear enoght so that we can see each wire and a circuit schematic diagram (or sketch) would be helpful.

Can't get a photo but, i do have a schematic diagram of the PCB attached

westaust55 · May 3, 2009

Okay. So at least we are clear that the SEROUT 7, N2400 part is correct.

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