Jump to content

Please help newb with LCD


Guest Allen
 Share

Recommended Posts

Guest Allen

Hi all,

I'm building a Midimon using a complete core kit I purchased from SmashTV. I'm getting no characters on my LCD, and belive I'm missing something in the hookup.

The details: The LCD is from Crystalfontz, p/n CFAG123864B-YYH-V, a 128x64 with built in inverter using a KS0108 compatible controller. The core seems to be functional after MIDI flashing using MIOS 1.6 and the main.syk file. When I power up the core I get 1 burst of sysex and then no output, which seems normal. I have a 10k pot between the -5v out of the LCD and gnd with the wiper going to Vo of the LCD, and can see the contrast of the LCD change as I turn the pot- so that seems to be working.

I'm unsure if the RS pin from the core should go to RST pin of the LCD, or if it (the reset line) should be tied high (it is active low). Also, the LCD has a D/I line to determine if the incoming byte is data or instruction, but I don't know where to connect this to the core. Sorry to be so verbose, but this is my first LCD project- any help would be greatly appreciated.

Allen

Link to comment
Share on other sites

  • 2 weeks later...

Hello Thorsten,

I'll try connecting the RS pin from the core to the D/I pin of the LCD and update the topic with the results.

I'll also check the LCD type in MIOS ID header, but I'm pretty sure I set that correctly.

Does this mean that there is no connection required to the RST pin of the LCD?  In my configuration, every other core to LCD pinout matched except the RS, CS3, and CS4 or the core and the RST and D/I or the LCD.  If the RS from the core connects to the D/I of the LCD, that still leaves the CS3 and CS4 of the core unconnected.  Is this a problem?

Thanks.

xile

Link to comment
Share on other sites

Hi,

RST is the reset line, it depends on the display if it has to be connected or not. In fact there are 5 possibilities:

*general answer mode on*

  • no reset pin: thats the common case
  • floating low-active reset pin (reset with logic-0): add a pull-up resistor (10k to +5V) so that the display is not in reset state after power-on
  • floating high-active reset pin (reset with logic-1): add a pull-down resistor (10k to ground) so that the display is not in reset state after power-on
  • low-active reset with internal pull-up: let it open
  • high-active reset with internal pull-down: let it open

*general answer mode off*

How to find out the type of reset pin? Normaly it can be read in the datasheet, and if not, try an external 10k pull-up first (in most cases the reset line is a low-active input) - if it still doesn't work, try a pull-down.

CS3 and CS4 are output signals of the core, so: no problem. You could connect a second KS0108 type display in parallel to the first one, with the only difference that the chip select lines are connected to CS3/4 in order to double the resolution (nice for MIDIbox LC)

Best Regards, Thorsten.

FAQMARKER

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...