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Feb 12 16 3:21 PM

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I've spent many hours trying to get a 64128A going, but the only instructions it will respond to are to turn the entire display black and then back to normal, and to invert black and white and then go back to normal.  I did get one line (a page, 8 dot rows high) to show up—once—and then could not do it again (although the previously mentioned commands still work).  I have not found a data sheet on Displaytech's site than matches this LCD exactly.  I have the data sheets for both the S6B1713 and NT7534 controllers, although it looks like the small differences between those two don't affect what I've been trying to do so far.  I think this LCD has the S6B1713, but if we put it in a product, I suspect the current-production ones may have a different controller IC.  What tricks are there to getting this thing going?  I've spent a lot of time in the FAQs and reading forum topics here, and have come up with nothing.  I found something in someone's private website that got me as far as I've gotten (mentioned above) so obviously the connections are ok, but I must be doing something wrong in the setup, or maybe not waiting long enough between commands (although I don't see anything in the data sheet requiring more than a quarter of a microsecond), or who knows what.  I've also emailed Displaytech, and I get no response.  Please help.
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#1 [url]

Feb 16 16 4:26 PM

Hi Garth,The 64128A display is being replaced by the 64128P as the driver chips were discontinued by the manufacturer. Here is a link to RS Electronics where you can find the 64128A datasheet: [/urlhttp://uk.rs-online.com/web/p/lcd-monochrome-displays/5326997/][/url[/url[/url]]]. The timing is different for the new driver chips which is probably why you are getting inconsistent results. If you haven't already found it, here is a Sourceforge site with a driver written in C for the 64128A: [/urlhttps://sourceforge.net/projects/graphicslcddriv/][/url[/url[/url]]]. You should be able to adapt it for your micro-controller. We are working to make the older datasheets available directly on our website. Please write if you are still encountering problems.

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#2 [url]

Feb 17 16 1:25 AM

Thanks for the response.  As I said in the title, I'm using SPI (serial) mode; but there is nothing in those pages and their links about using it in serial—only parallel.  I will go through the data sheet there with a fine-toothed comb for differences in the instructions though tomorrow when I get time though.

Last Edited By: Garth Feb 17 16 2:27 AM. Edited 2 times.

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#3 [url]

Feb 17 16 11:00 AM

This display is parallel only. You will need an 8-bit parallel port for data and 5 GPIO pins for control (RS, R/W, E, CS1, CS2) to use this display. You can use 8 GPIO pins to emulate a parallel port if needed. We have TFT displays that contain a more sophisticated driver chip that can be configured for either parallel or SPI operation, but this display doesn't have that option.

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#4 [url]

Feb 18 16 10:21 PM

That's a little hard to believe, because after going through the initialization sequence of instructions all on SPI (setting the direction, power control, voltage regulators, LCD bias, etc.), per the data sheet, this display does respond properly by SPI to turn the display on (instruction $AF), and to the  instructions to turn the whole display dark (instruction $A5), and back to normal (instruction $A4), and to invert it (white dots to black, and black dots to white, instruction $A7), and back to normal (instruction $A6), and I did get a line of data into it once, although I have not been able to repeat getting a line of data in.  Jumper 3 (a solder blob) is installed to get SPI.

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#5 [url]

Aug 2 16 1:34 AM

Now after many months of having the project backburnered, I've ordered a newer LCD, but I also got this one mostly working, in SPI.  I had had one bit wrong in one of the instructions, and that had been keeping it from working.  Other controller ICs for this size of LCD have nearly identical instruction sets.  My only problem with it now seems to be that the contrast is very, very poor.  Doing 1/9 or 1/7 bias seems to make no difference.  Any tips?

Edit, later:  Somehow the problem of the poor contrast has also resolved itself now too.  In the conflicting data sheets I have, one says this model is 5V.  I'm using it at 3.3V, but everything is working correctly now, and the contrast is what I would expect from such a graphic LCD (which is good, but not as good as the STN intelligent character LCDs).

Last Edited By: Garth Aug 11 16 4:06 PM. Edited 1 time.

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