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I am using a KS0108 compatible graphic LCD (JHD12864E). I was wondering if there is a method to see if the lcd is working or not with a simple test. I tried sticking 5 volt between vcc and ground but nothing lights up. Is there a way I can test this module without messing around with the wires on the breadboard?

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4 Answers 4

It is not possible to test the module without wiring it to a microcontroller.
When power is applied to the module, the display remains off and uninitialized. In order to turn on the display, you need to initialize the display with certain commands and parameters. After which you can send characters to the display. This requires it to be wired to an intelligent chip like a microcontroller that can carry out the commands to initialize the module.

Edit: There are also other impractical ways to drive these modules as suggested in other posts.

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Well, it can be operated without a microcontroller, but it's a very slow process and does require some external components. –  Ignacio Vazquez-Abrams Jan 15 '13 at 6:49
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@IgnacioVazquez-Abrams Sure, there will always be N+1 ways. I did not said that microcontroller is the ONLY way. It can be connected to PC parallel port, PC serial port, USB port, etc. You can use an ASIC, FPGA, etc. as well. Just needs logic to drive it. –  Chetan Bhargava Jan 15 '13 at 6:52
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@ChetanBhargava actually you did "It is not possible ... without ... a microcontroller". –  Passerby Jan 15 '13 at 8:25
    
@Passerby edited my post and added impractical ways. Thanks for your suggestion. –  Chetan Bhargava Jan 15 '13 at 15:33

Unfortunately all of the LCD modules that I have worked with, whether they be graphic or character mode types, have required a "smart source" to check out whether they work.

Sometimes you can be lucky with character mode types and connect them in place of an existing display on another piece of equipment to see if that can drive some content on the display for test purposes.

For graphic mode displays it is highly unlikely that you can get it to display something unless you cobble up an interface and program the sequences needed to "talk" to the display module's controller chip. Part of the difficulty comes into play because there are many varieties of graphic displays using many different display controller chips that all work a bit differently from one another. To make matters even more difficult for the graphic displays is that the interface connection to the display will be different pinning and connector type for each model of display.

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There is no self test mode with the JHD12864E lcd, nor with the KS0108 compatible controllers. These lcds are always manufactured for production use, so it's expected that an appropriate test system (microcontroller) is setup by the end user. Since you say you don't want to mess around with your breadboard or wires, that's pretty much the answer, no.

That said, the protocol for the KS0108 lcd controller is pretty simple. It's essentially a variation on the HD44780 character lcd controller (The difference being that the HD44780 has a built in character generator map [i.e. Fonts and Alphabet]). The pinout and protocol is roughly the same. You can test the lcd with Tedious flipping of switches. And you can combine that with a 555 timer, to rapidly fill or clear the lcd with a specific pattern. (Set the initialization bytes by hand, then set up the 555 timer to fill in the rest of the lcd by toggling the E pin. Or just rapidly hit the E switch).

There are ways of doing this without a microcontroller/code, but you are way better off with one, instead of the frustrating dipswitch method.

enter image description here

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No, that is not possible. The display may show some pixels when you connect Vcc, ground, Vout and Vo, but you cannot tell if everything's working.

For correct connections: (forget about the PIC)

enter image description here

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Will the display always show some pixels when it is supplied with power only?I don't want to know if the GLCD works correctly;I just want to know if it's working. In my case,the GLCD is blank when I power it up. Not even a single pixel is glowing up. Is the GLCD already dead? –  Adithya Dec 15 at 16:56
    
@Adithya it depends on the controller. The best would be to ask a new question (and perhaps add a link to this one for reference) with your specific situation and question. –  Camil Staps Dec 15 at 16:58
    
Yes,sure. My GLCD is based on a KS0108 driver. –  Adithya Dec 15 at 17:00
    
@Adithya please use the 'Ask question' like I gave or the button in the top right of the site to ask a new question. –  Camil Staps Dec 15 at 17:01

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