Serial LCD problem

Started by Carlos Eduardo Alves Cardoso March 15, 2007
Hello y'all

I've just started with BasicX and so far it's not very hard...

However I've been having problems connecting the serial LCD. I have
a BX-24 and a development kit with a socket that connects the LCD's
RX pin to pin number 5 in the BX-24.

I've already went through all the LCD examples I could find and
still haven't figured out to put it to work. Or even configure, for
that matter.
All I get is the LCD's top line all dark and the bottom one with
nothing on it. What could the problem be? I've worked with displays
before (parallel addressed) and the only time I had problems like
these was when I didn't configured them.

Any ideas on what the problem could be? Anyone with this problem?
Any examples that I could try that I haven't seen yet? :\

Thanx in advance, Carlos Cardoso
Carlos,

Is this one of our older 2x16 serial LCDs? It would have a 14 pin
socketed Z8 CPU on it if it was.

These had an issue where the Z8 would power up and start talking
with the LCD before the +5 power was good. This would cause the
LCD to lock up and give the display you described.
Here is a simple test program that uses pin5
' Define Com3 buffers
Dim Com3In(1 to 20) As Byte
Dim Com3Out(1 to 30) As Byte
Dim Foo As Byte

'************************************************************
Sub Main()

' ********* Open Com3 for the LCD
Call OpenQueue(Com3In, 20)
Call OpenQueue(Com3Out, 30)
' Set Com3
Call DefineCom3(0, 5, bx1000_1000) ' Use BX-24 Pin 5
Call OpenCom(3, 9600, Com3In, Com3Out) ' Open Com3
Call Sleep(200)' Wait after power up for LCD to stabilize

' Set the Contrast *** Adjust value for older LCDs****
Call PutQueueStr(Com3Out, Chr(19) & Chr(40))
' Set backlight to full brightness
Call PutQueueStr(Com3Out,Chr(20) & Chr(250))

Do

' Clear the screen
Call PutQueueStr(Com3Out, Chr(12))
' Display "Hello World" and the value Foo
Call PutQueueStr(Com3Out, "Hello World! " & CStr(Foo))
Foo = Foo + 1
If Foo = 255 Then
Foo = 1
End IF
Call Sleep(200)

Loop

End Sub

----- Original Message -----
From: "Carlos Eduardo Alves Cardoso"
To:
Sent: Thursday, March 15, 2007 12:52 PM
Subject: [BasicX] Serial LCD problem
> Hello y'all
>
> I've just started with BasicX and so far it's not very hard...
>
> However I've been having problems connecting the serial LCD. I have
> a BX-24 and a development kit with a socket that connects the LCD's
> RX pin to pin number 5 in the BX-24.
>
> I've already went through all the LCD examples I could find and
> still haven't figured out to put it to work. Or even configure, for
> that matter.
> All I get is the LCD's top line all dark and the bottom one with
> nothing on it. What could the problem be? I've worked with displays
> before (parallel addressed) and the only time I had problems like
> these was when I didn't configured them.
>
> Any ideas on what the problem could be? Anyone with this problem?
> Any examples that I could try that I haven't seen yet? :\
>
> Thanx in advance, Carlos Cardoso
>
> Yahoo! Groups Links
>
Hi,
I have had a similar problem but not with Serial LCD's but with HD44780
lcd's. They do the exactly the same thing, first line dark and the second
line is blank. Can anyone fix this?
Andy,

There is an example program an library for talking to raw LCDs on the
BasicX.com examples page called
Controlling a HD44780 based Parallel LCD. You may not be waiting long enough
after power
up before talking to it.

Regards,

Chris
----- Original Message -----
From:
To:
Sent: Thursday, March 15, 2007 1:33 PM
Subject: Re: [BasicX] Serial LCD problem
> Hi,
> I have had a similar problem but not with Serial LCD's but with
> HD44780
> lcd's. They do the exactly the same thing, first line dark and the
> second
> line is blank. Can anyone fix this?
>
>
> Yahoo! Groups Links
>
Nop, There's an 18 pin Zilog SL1925 (Z86E0208PEC) in the back and the
program you've supplied had no effect on it. I also seem to notice
that the top row is a bit dim, but since there is commands for the
contrast adjustment I think that it might not be a problem.
Could it be the two jumpers in the back? I have both of them in
place.

It's a tricky problem this one... :\ I think I might try and use the
PC's serial port to test the LCD and start eliminating possible
causes! :\

Thank you for your comments! ;)

--- In b..., "Chris" wrote:
>
> Carlos,
>
> Is this one of our older 2x16 serial LCDs? It would have a 14 pin
> socketed Z8 CPU on it if it was.
>
> These had an issue where the Z8 would power up and start talking
> with the LCD before the +5 power was good. This would cause the
> LCD to lock up and give the display you described.
> Here is a simple test program that uses pin5
> ' Define Com3 buffers
> Dim Com3In(1 to 20) As Byte
> Dim Com3Out(1 to 30) As Byte
> Dim Foo As Byte
>
> '************************************************************
> Sub Main()
>
> ' ********* Open Com3 for the LCD
> Call OpenQueue(Com3In, 20)
> Call OpenQueue(Com3Out, 30)
> ' Set Com3
> Call DefineCom3(0, 5, bx1000_1000) ' Use BX-24 Pin 5
> Call OpenCom(3, 9600, Com3In, Com3Out) ' Open Com3
> Call Sleep(200)' Wait after power up for LCD to stabilize
>
> ' Set the Contrast *** Adjust value for older LCDs****
> Call PutQueueStr(Com3Out, Chr(19) & Chr(40))
> ' Set backlight to full brightness
> Call PutQueueStr(Com3Out,Chr(20) & Chr(250))
>
> Do
>
> ' Clear the screen
> Call PutQueueStr(Com3Out, Chr(12))
> ' Display "Hello World" and the value Foo
> Call PutQueueStr(Com3Out, "Hello World! " & CStr(Foo))
> Foo = Foo + 1
> If Foo = 255 Then
> Foo = 1
> End IF
> Call Sleep(200)
>
> Loop
>
> End Sub
>
> ----- Original Message -----
> From: "Carlos Eduardo Alves Cardoso"
> To:
> Sent: Thursday, March 15, 2007 12:52 PM
> Subject: [BasicX] Serial LCD problem
> > Hello y'all
> >
> > I've just started with BasicX and so far it's not very hard...
> >
> > However I've been having problems connecting the serial LCD. I
have
> > a BX-24 and a development kit with a socket that connects the
LCD's
> > RX pin to pin number 5 in the BX-24.
> >
> > I've already went through all the LCD examples I could find and
> > still haven't figured out to put it to work. Or even configure,
for
> > that matter.
> > All I get is the LCD's top line all dark and the bottom one with
> > nothing on it. What could the problem be? I've worked with
displays
> > before (parallel addressed) and the only time I had problems like
> > these was when I didn't configured them.
> >
> > Any ideas on what the problem could be? Anyone with this problem?
> > Any examples that I could try that I haven't seen yet? :\
> >
> > Thanx in advance, Carlos Cardoso
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
>
Sorry, I meant 18 pins. Yes, that's the part. On these parts you
need to make sure your 5v is truly 5.0 - 5.3 volts any less and
you may have problems.

Some of those Z8's had a strange manufacturing defect in their power
up section that caused some of them to start running before the power
was good which would lock up the LCD.

If you purchased the LCD less than 90 days ago you can have it
exchanged for a newer version.
Chris
----- Original Message -----
From: "Carlos Eduardo Alves Cardoso"
To:
Sent: Friday, March 16, 2007 6:58 AM
Subject: [BasicX] Re: Serial LCD problem
> Nop, There's an 18 pin Zilog SL1925 (Z86E0208PEC) in the back and the
> program you've supplied had no effect on it. I also seem to notice
> that the top row is a bit dim, but since there is commands for the
> contrast adjustment I think that it might not be a problem.
> Could it be the two jumpers in the back? I have both of them in
> place.
>
> It's a tricky problem this one... :\ I think I might try and use the
> PC's serial port to test the LCD and start eliminating possible
> causes! :\
>
> Thank you for your comments! ;)
>
> --- In b..., "Chris" wrote:
>>
>> Carlos,
>>
>> Is this one of our older 2x16 serial LCDs? It would have a 14 pin
>> socketed Z8 CPU on it if it was.
>>
>> These had an issue where the Z8 would power up and start talking
>> with the LCD before the +5 power was good. This would cause the
>> LCD to lock up and give the display you described.
>> Here is a simple test program that uses pin5
>> ' Define Com3 buffers
>> Dim Com3In(1 to 20) As Byte
>> Dim Com3Out(1 to 30) As Byte
>> Dim Foo As Byte
>>
>> '************************************************************
>> Sub Main()
>>
>> ' ********* Open Com3 for the LCD
>> Call OpenQueue(Com3In, 20)
>> Call OpenQueue(Com3Out, 30)
>> ' Set Com3
>> Call DefineCom3(0, 5, bx1000_1000) ' Use BX-24 Pin 5
>> Call OpenCom(3, 9600, Com3In, Com3Out) ' Open Com3
>> Call Sleep(200)' Wait after power up for LCD to stabilize
>>
>> ' Set the Contrast *** Adjust value for older LCDs****
>> Call PutQueueStr(Com3Out, Chr(19) & Chr(40))
>> ' Set backlight to full brightness
>> Call PutQueueStr(Com3Out,Chr(20) & Chr(250))
>>
>> Do
>>
>> ' Clear the screen
>> Call PutQueueStr(Com3Out, Chr(12))
>> ' Display "Hello World" and the value Foo
>> Call PutQueueStr(Com3Out, "Hello World! " & CStr(Foo))
>> Foo = Foo + 1
>> If Foo = 255 Then
>> Foo = 1
>> End IF
>> Call Sleep(200)
>>
>> Loop
>>
>> End Sub
>>
>> ----- Original Message -----
>> From: "Carlos Eduardo Alves Cardoso"
>> To:
>> Sent: Thursday, March 15, 2007 12:52 PM
>> Subject: [BasicX] Serial LCD problem
>> > Hello y'all
>> >
>> > I've just started with BasicX and so far it's not very hard...
>> >
>> > However I've been having problems connecting the serial LCD. I
> have
>> > a BX-24 and a development kit with a socket that connects the
> LCD's
>> > RX pin to pin number 5 in the BX-24.
>> >
>> > I've already went through all the LCD examples I could find and
>> > still haven't figured out to put it to work. Or even configure,
> for
>> > that matter.
>> > All I get is the LCD's top line all dark and the bottom one with
>> > nothing on it. What could the problem be? I've worked with
> displays
>> > before (parallel addressed) and the only time I had problems like
>> > these was when I didn't configured them.
>> >
>> > Any ideas on what the problem could be? Anyone with this problem?
>> > Any examples that I could try that I haven't seen yet? :\
>> >
>> > Thanx in advance, Carlos Cardoso
>> >
>> >
>> >
>> >
>> >
>> > Yahoo! Groups Links
>> >
>> >
>> >
>>
> Yahoo! Groups Links
>