NHD-320240WX-COTFH-V#I041 w/ 6809 uP

garyneal
I just recently bought the subject graphics display from Jameco:

http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=2190418&

The product was advertised as a 5 volt device but upon closer examination it appears to be powered by 3.3 volts.  That is not a problem but I am kind of confused and need some clarification on a couple of things.  I apologize for the newbie question but I have not actually built a project that utilizes an LCD display before and I want to ensure that I interface the uP and the device up correctly.  The product specs sheet shows on page 4 that the VSS and VDD terminals are both wired to the same VSS and VDD terminals of the MPU.  Since the 6809 is a 5 volt device does the LCD device accept a 5 volt supply or is that an error on the specs sheet?  If it is an error does that mean that the data and control lines from the MPU require level shifting to 3.3 volts or can they be wired directly to their corresponding pins of the LCD device?

Lastly, SEL1 line is indicated as non connected and a jumper JSEL selects the SEL1.  Is this device configured for the 6800 family MPU or 8080 family?

Thanks for your help.
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7 comments

Date Votes
  • garyneal

    I dug a little deeper and found on page ten of the RA8835 controller manual that its VDD may be the same supply as the controlling processor.  If, as I suspect, this is the same VDD pin as the subject product then it does not appear that I need a 3.3 volt regulator and level shifting.  Can someone confirm this, please?

    That still leaves one other question.  How is the SEL1 line configured on the device?

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  • Paul_B

    Hello,

    Thank you for reaching out. NHD-320240WX-COTFH-V#I041 is a 3.3V module not 5V. We will work with Jameco to have the part description corrected on their website.

    In the mean time please review the datasheet for NHD-320240WX-COTFH-V#I041:

    https://newhavendisplay.com/content/specs/NHD-320240WX-CoTFH-VI041.pdf

    Regarding SEL1, by default the LCD is set up for 8080, if you move the jumper down one pad it will be configured for 6800.

    Hope this helps!

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  • garyneal

    Paul,

    Thanks, but your document brings me back to my original questions regarding powering this device.

    On page four of that specs document, the schematic showing the interface between the LCD device and the MPU has the power and ground lines of both devices tied together.  The 6809 is a five volt device so is that page wrong or am I allowed to power the device with 5 volts as indicated on page ten of the RA8835 controller manual linked on page five of the manual you linked?

    If that page is wrong and the LCD device requires a separate 3.3 volt supply then do the address line, data lines, read/write line, etc. also need to be shifted to 3.3 volts from 5 volts?

    Thanks again.

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  • Paul_B

    Hello,

    Page four in the displays datasheet does not list power and GND tied together. The upside-down triangle represents ground and the right-side up triangle represents power.

    NHD-320240WX-COTFH-V#I041 is a 3.3V module and the logic is 3.3V, you should not connect 5V to this display.

     e.g. When connecting NHD-320240WX-COTFH-V#I041 to an Arduino Board (which is 5V logic), this will require level shifting for the I/O pins.

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  • garyneal

    I did not mean power and ground were tied together.  I meant that the MPU's power and GND were common with the display's power and GND.  I understood what the triangles meant.  

    Your specs sheet should make it clearer that the MPU may not be directly connected to the device as indicated on page four if the MPU is powered by five volts.

    Thanks

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  • garyneal

    One more question.  I dumb one, I know, but I just want to make certain.

    Can I interface the 6809 MPU (a five volt device) directly with the NHD-320240WG-BxTFH-VZ# device as shown on page four of the following document?

    https://newhavendisplay.com/content/specs/NHD-320240WG-BxTFH-VZ.pdf

    This device is listed to be either a 5 volt or a 3.3 volt device.

    Thanks

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  • Michael_L

    Yes, this display can be used with a 5V microcontroller directly.

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