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Newbie mircemp
Registered: ‎03-08-2011

Sending commands to serial LCD(Pmod cls) in vhdl

Hello everybody,

I am quite a beginner in the field of fpga and vhdl and I did stumble across a problem...

How can I send the specific command bytes to an LCD in vhdl.

I worked with arduino and there the routine was actually simple after I set the baud rate I used to send some bytes and thouse were the commands.But in vhdl how do I set the baud,is it necessary to set it if so after I set it How do I transmit the command  bytes and after that the message strings themselves?

Usually when i worked with serial lcd's(and arduino) i used to need only the gnd the vcc and the rx pin because i would set the tx on the board was using is it possible to do so here to if for example i use a uart communication?

http://www.digilentinc.com/Data/Products/PMOD-CLS/PmodCLS_rm_RevD-E.pdf    -> here is the data sheet for the serial lcd i am using.


Thanks in advanced :smileywink:


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4 Replies
Teacher eteam00
Registered: ‎07-21-2009

Re: Sending commands to serial LCD(Pmod cls) in vhdl

In addition to the items you list, you are also new to serial interfaces, UART operation, and UART design.


Look through your design for a UART module (there isn't a single standard UART module, just as there is no single chair or kitchen table design).  Hopefully the UART module you are using has some helpful comments which will help you learn how UARTs work.


For some more background on serial interfaces, start here.


- Bob Elkind

README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

1. Read the manual or user guide. Have you read the manual? Can you find the manual?
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5. Students: Copying code is not the same as learning to design.
6 "It does not work" is not a question which can be answered. Provide useful details (with webpage, datasheet links, please).
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Registered: ‎02-25-2008

Re: Sending commands to serial LCD(Pmod cls) in vhdl

Your problem is that you are used to writing microcontroller firmware for your Arduino. That's sequential software design.


FPGAs are hardware designs. This is a different skill set.

----------------------------Yes, I do this for a living.
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Advisor eilert
Registered: ‎08-14-2007

Re: Sending commands to serial LCD(Pmod cls) in vhdl

Hi ,

a good staring point for you would be to take a look at the PicoBlaze processor ressources.

KCPSM3 comes with a ready to use UART and there's plenty of good documentation.

(Also an extra forum for Picoblaze related topics, where you can find answers to most beginners questions)


Have a nice synthesis


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Newbie vlad0007
Registered: ‎03-22-2011

Re: Sending commands to serial LCD(Pmod cls) in vhdl

i am also interested in this subject

Can anyone please send or post an example code for showing some letters on the PMod CLS lcd screen.

I have readed about the uart, i`ve implemented it but with no success in send commands or text messages to cls


Please help me or us!

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