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Altera_Forum
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14 years ago

Altera DE0-nano with an LCD connected

Hey everyone,

for a project of mine I am using the Altera DE0-nano board. I want to display some text on a 2x16 LCD which is connected via GPIO_0. The controller for the LCD is HD44780 compatible. So I thought I could reuse the code from the Altera DE2 LCD demo (which uses the HD44780 LCD controller). But unfortunately I am not able to display anything on the LCD. I tried to set the voltages of the pins to 3.3-V LVTTL and to 2.5-V but this did not make a difference. Any advice on what I should do?

Thanks a lot!

8 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    What is the part number of the LCD module?

    Some of them are 5V-only.

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    It can also be operated using 3.3V (p. 11), but the GPIO on the board delivers 5V or 3.3V depending on what VCC you use. I'm running it in 5V operation mode. Does this mean that I need at least a voltage of 3.5V in order to get a high signal?

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    --- Quote Start ---

    It can also be operated using 3.3V (p. 11), but the GPIO on the board delivers 5V or 3.3V depending on what VCC you use. I'm running it in 5V operation mode. Does this mean that I need at least a voltage of 3.5V in order to get a high signal?

    --- Quote End ---

    No, it means you'll damage your DE0-nano board.

    Do not operate it at 5V unless you have either level translators or voltage clamps (I'm pretty sure the DE0-nano does not have them).

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    --- Quote Start ---

    Why should it damage the board?

    --- Quote End ---

    It will damage the FPGA on the board.

    The FPGA is a Cyclone IV, which is not 5v tolerant.

    --- Quote Start ---

    On each GPIO are two different VCC's: VCC_SYS and VCC3P3. According to the user manual (http://www.terasic.com.tw/cgi-bin/page/archive_download.pl?language=english&no=593&fid=75023fa36c9bf8639384f942e65a46f3) VCC_SYS is 5V and VCC3P3 is 3.3V. But I can't get voltages beyond 3.3V for the pins. So I need to change the voltage for the LCD to 3.3V and the voltage of the pins to 2.5V, right?

    --- Quote End ---

    p17 "DE0-Nano board provides two 40-pin expansion headers. Each header connects directly to 36 pins of the Cyclone IV E FPGA, and also provides DC +5V (VCC5), DC +3.3V (VCC33), and two GND pins"

    Read the comment clearly: "connects directly to the FPGA pins".

    You need to change the LCD to 3.3V, and leave the FPGA I/Os at 3.3V.

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    I have a problem with the DE0 nano when I put the LCD driver in Sopc Builder .... I compile a code and don't have error then run the code and even print something to the console...... any code execute