Communicate serially with a MOP Character LCD?

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jkerr
LCD?
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Communicate serially with a MOP Character LCD?

Post by jkerr » Wed Sep 28, 2005 2:33 pm

Is it possible to communicate serially with part # MOP-AL162A-BBTW. My idea is to use a Serial In/Parallel Out shift register such as National part # 74F164A. Connect the shift register outputs to DB0-DB7 on the LCD. Use the CLK from my microprocessor and clock in 8 bits to the shift register outputs. When all eight bits are clocked in, then set the Master Clear on the shift register to clear the outputs and then clock in 8 more bits. Will this work?

Tom
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Post by Tom » Thu Sep 29, 2005 9:13 am

Hi jkerr,

Thank you for posting on the forum.

What you want to attemp can be done, but it will be extremely difficult to perform. You will still need to use the extra pins to change toggle the enable pin and the R/W pins. You must also worry about the timing of the data pins. You should refer to the timing diagram of the display in section 13 of the manual at http://www.matrixorbital.com/files/MOP-AL162A.pdf

I wish you good luck getting everything to work.

If you have anymore questions or concerns, please feel free to post them.

Best Regards,

Paradigm
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Post by Paradigm » Thu Sep 29, 2005 11:24 am

To expand on Tom's reply: unless you really know what you are doing or have an extreme ammount of patience, I wouldn't recommend it. The timing between control signaling and data signaling has to be maintained otherwise the display won't respond at all. At the very least, put the display into 4 bit mode so you only need 4 data pins to it, and tie each pin to the controller. This will be MUCH easier than using a shift register.

The complexity of talking to a parallel display is the reason why we offer serial displays. They are just so much simpler. For the small run/hobbiest, I see no reason to get a parallel display unless you just want to experiment. If you want a no-frills approach on a budget. Try the MOS series. For the embedded market, there will be a two-wire interface version released by 1Q 2006 called the MOI series.

That being said, or main parallel customers are larger companies that want to custom design our displays into complex systems. In other words, the people who have the time to fool around with these things enough to get them working.
James McTavish, P.Eng
Director of Engineering
Matrix Orbital

jkerr
LCD?
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Joined: Wed Sep 28, 2005 2:22 pm

Post by jkerr » Thu Sep 29, 2005 12:57 pm

The reason I was going with a MOP instead of the MOS is in quantities of 500+ the MOP is a LOT less expensive (according to the website). The MOS-AL162A-BW is $29.95 compared to the MOP-AL162A-BBTW which is $11.47 in quantities of 500+.

The reason I want to control the MOP serially is for cost reasons too. The company I work for we design mobile satellite systems. So the main control electronics and satellite are on top of the vehicle while the LCD would be on the inside of the vehicle. The least amount of wires ran into the vehicle the better. While it would be a bundled cable, the amount of wires in the bundle matters. I haven't looked into it very much, but how many wires would I need if I went with the 4-bit approach?

By running it serially, I figured I would need four wires... Enable, R/W, Data, and the Master Clear on the shift register. Using the 8-bit approach I would need 10 wires correct?... Enable, R/W, and the DB0-DB7. Using the 4-bit approach I would need 6 wires?... Enable, R/W, and DB4-DB7.

Is this correct? If so, using the 4-bit approach seems like a better option than serially since I would only be gaining two wires. Just curious but how many wires would need to be ran if I used a MOS series LCD?... 3?

Thanks
Jon

Raquel
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Post by Raquel » Thu Sep 29, 2005 1:54 pm

Hi Jon,
If you are to try and use the MOS series, the only wires you will need to connect are RX, TX and of course, gnd. The controller that you have outside the vehicle most likely would have some serial interface, UART for the case of the MOS is the one to use. The ease of controlling the display via the MOS module will be the big factor of difference with the MOPs. You'll be surprised how much more you can do with the MOS and how much easier it will be to implement on the controller outside the vehicle; be it harware (wires and connections) or software.
Thank you very much for your post
Raquel Malinis
Design and Development
Matrix Orbital

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