LCD display, connecting the dots...
Moderator: Guido Körber
LCD display, connecting the dots...
Hi all,
I am very new to the world of electronics and I have problems connecting a LCD display(4x40 char, type ym4004-01). The display has the correct controller and has room for 18 wires numbered 1 till 18. Now my wonderful IOWarrior24 has 16 pins... Obviously I do not know which pin I should connect to which hole on the LCD display. To make matters more interesting I do not have a datasheet for the LCD display. Are there any conventions I should follow(connect hole 1 on the LCD with pin 1?)? What is the numbering on the pins on the IOWarrior? The docs weren't quite clear(page 9, section 4.2.2 contradicts page 26, section 8.4.4, I think it is only for IOW40.)
Thanks in advance!
Harm
I am very new to the world of electronics and I have problems connecting a LCD display(4x40 char, type ym4004-01). The display has the correct controller and has room for 18 wires numbered 1 till 18. Now my wonderful IOWarrior24 has 16 pins... Obviously I do not know which pin I should connect to which hole on the LCD display. To make matters more interesting I do not have a datasheet for the LCD display. Are there any conventions I should follow(connect hole 1 on the LCD with pin 1?)? What is the numbering on the pins on the IOWarrior? The docs weren't quite clear(page 9, section 4.2.2 contradicts page 26, section 8.4.4, I think it is only for IOW40.)
Thanks in advance!
Harm
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Have a look at our application note #5: Driving Display Modules With IO-Warrior
4x40 displays usually use two controller chips. To drive this display with IOW24 requires some additional circuit (see app note 5).
If you don't have the pinout of the display module you are out of luck. You can of course just try if it follows the usual pinout but you might as well blow up the display trying this.
4x40 displays usually use two controller chips. To drive this display with IOW24 requires some additional circuit (see app note 5).
If you don't have the pinout of the display module you are out of luck. You can of course just try if it follows the usual pinout but you might as well blow up the display trying this.
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Got it(http://en.wikipedia.org/wiki/HD44780_Character_LCD)! I should have asked Wikipedia first. Thanks for your help.
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Yes, right. Though since quite a few displays have the connector pins in a single row you would have to do some hand soldering in any case. If you use only half of the display then wiring is not too hard using the 16 pin connector. But to drive the second chip you need to add the circuit to select the E signal.
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Forgot to add: Quite a few of the connections can be found out by looking at the display. If pin 6 has no conenction then you can be sure that both E signals can be found above pin 14. Check the pins 17&18 if they are connected to anything that looks like it could be the backlight.
Though there may be an EL backlight in the module. LED backlights can be easily powered by 5V, but EL backlights need voltage boosters as they run with 70V or more.
Though there may be an EL backlight in the module. LED backlights can be easily powered by 5V, but EL backlights need voltage boosters as they run with 70V or more.
I am pretty sure I just have a LED backlight. So that such be OK. I'll give not connecting pin 6 a try. If I do not connect him, I should see nothing right? Then I can slowly try 15 and 16 and as soon as I found out which is carries the E signal I can hook up the backlights to the remaining pins. Okay! That should do it. Thanks again.
On a related issue, I read in Application Notes 5 page 13 section 3.5 that I can make some additional circuitry in order to drive two hd44780 controllers. How ever I am puzzled by the 'Px.x' entry in both schemas. What do they represent? I can only find P0.0, P0.1 etc. And I can't believe 'Px.x' means 'just get any of the P pins'. Or is it?
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Alright, I think I have everything connected. However I do not know how exactly use the sample program IOWarriorProber. I assume the LCD display is set on interface 0? Then I send an 'Enable LCD Mode' followed by a 'init display' followed by a 'write to display'. Is this the correct way of doing it?
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If the contrast setting is correct you should see faint rectangles as soon as you apply power to the module. Once you initialize the module it depends on the mode you set if you will see anything. If you clear the display and don't activate the cursor you should see nothing. The rectangles should fade when you initialize the display.
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Re: LCD display, connecting the dots...
Hey there,
I have 4*40 ym4004 lcd. but i dont know how to send characters(commands) to the lcd. Can u give a simple example or link a data sheet? thank you...
I have 4*40 ym4004 lcd. but i dont know how to send characters(commands) to the lcd. Can u give a simple example or link a data sheet? thank you...