GLCD MTB-368 (122*32 SED1520) with openGLCD and Teensy 3.0

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After finding the cheapest transmissive graphic LCD on eBay, I've been trying to get it going with my Teensy 3.0. Following the u8glib thread where Bill Perry posted about his openGLCD library, I've attempted to apply Hoss' modifications and other tips in the thread, but to no avail.

My board is made by ETT in Thailand. They furnished a data sheet after I emailed them, as strangely the online resources are in Thai only. It's controlled by dual SED1520s, with 61*32 each. The display handles backlight/contrast internally.

Curiously, the data sheet seems require a 2KHz clock and an E pin. openGLCD's SED1520 device file states SED1520 does not need an E pin, nor does it have clock support. In an effort to get it going, I tried it high, low, and floating.

Following the wiring diagram in the openGLCD manual, I've set Teensy (GLCD) pins:
16 to 23 (10 to 17) for D0...D7
RW (9) is 8
DI (4) is 9
CS1 (5) is 3
CS2 (6) is 2
GLCD pin 8 is E, which is constant high.
GLCD pin 18 is also set high to select M68 bus style.

T5GV9Col.jpgCzY64YWl.jpg

openGLCD ManualConfig_sed1520-vk5121_Panel.h (modified) config attached.
View attachment ManualConfig_sed1520-vk5121_Panel.h
MTB-368 English datasheet attached.
View attachment User's Manual of GLCD MTB-368.pdf

As you can see from the clip below, the above wiring produces a series of mostly horizontal lines. Note that I used Bill P. and Paul S.'s quick and dirty technique of 10K Ohm resistors in series with each GLCD and Teensy pin, as the GLCD is 5V logic. I'm awaiting delivery of a 5V AVR-based board to do more testing.


Does anything stand out to you immediately, or might this particular display require some finessing of the libraries? Thank you for your time and assistance. :)

- Chris
 
I'll take a look at this later today, and get back to you.
--- bill

Just had a quick look at the datasheet.
I'm going to have to really dig into this as the signals appear to be quite different
from any of the other sed1520 displays I've seen.

One thing that isn't clear is whether the CL signal (glcd pin 7) is an input or an output.
It may actually be an output. None of the diagrams show it being connected.

How do you have the Vo (glcd pin3) hooked up? or did you leave it floating?

Where did you purchase this? I may need to buy one as well to test it.
 
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Just had a quick look at the datasheet.
I'm going to have to really dig into this as the signals appear to be quite different
from any of the other sed1520 displays I've seen.

The E and CLK confused me, as well, as it didn't seem to come up with SED1520 at all. On the other hand, SBN1661 chips, which seem to operate similarly to SED1520, apparently have external/internal clocks. This particular SBN1661 (see URL below) seems to alternate between an internal and external clock by way of the E pin. Internal clock requires the Vo be connected, while external has the Vo floating.

http://www.winstar.com.tw/products_detail_ov.php?lang=en&ProID=44

Is it possible this display could be driven SBN1661-type chips instead of the SED1520s?

One thing that isn't clear is whether the CL signal (glcd pin 7) is an input or an output.
It may actually be an output. None of the diagrams show it being connected.

This is a good question. I will post an update in a bit with the DMM reading from the CLK pin.

How do you have the Vo (glcd pin3) hooked up? or did you leave it floating?

Vo was left floating for all of my testing.

Where did you purchase this? I may need to buy one as well to test it.

I found it on eBay back in January. Apparently the seller has since closed up shop.
After spending 20 mins scouring eBay and the rest of the net, it seems it's presently available only from the manufacturer in Thailand. On the bright side, they responded very quickly with the English datasheet.
 
I'm working an update for the library to support this display.
It will require a new device file and a new config file.
pm me and we'll work off line to get it up and going.
--- bill
 
Support for this display has been added to openGLCD and will be available in the next release.
Unfortunately, it requires 2kHz clock signal but other than that, it works as expected
and is is now fully supported by the library.

--- bill
 
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