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Messages - Saurabh_B

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346
Hi,

The most similar controller inside the OLED display's is the ST7066U. The commands that are used for displays with this controller will be the same as the commands used by the OLED displays. The difference will be in the amount of time required to execute the commands or time to write the data onto the display.

There is a sample initialization sequence on pages 20 and 21 in the datasheet of the display. At the same time any program used for the  ST7066U will work for this display; but the code would need to have the timing adjusted for the new display.
The links for the datasheets for the OLED displays are here:
NHD-0420DZW-AY5
NHD-0220DZW-AY5

When we say timing issue it usually refers to the time between consecutive commands or data writes to the display. For instance with the ST7066U many of the commands will have a max execution time of 37us, where as the OLED display will have a max execution time of 600us.

If the time you give the commands to execute to the display are on the borderline of the max execution time the error wont occur at first, but over time you will start seeing various errors occur with the display such as a shift in the display.


347
The ST7066U can be used with either 3.3V or 5V depending on which LCD display it is used in. In this case the VDD is 5V so your minimum Vih would be 3.5.

348
OLEDs / Re: NHD-0420CW-AB3 contrast (brightness)
« on: August 12, 2015, 09:04:51 AM »
Unfortunately if you have it at the lowest setting allowed by the contrast control, there's nothing else you can do to the display.

You can however use a filter or an overlay to dim the screen.

349
OLEDs / Re: NHD‐0220DZW‐AY5 loosing columns
« on: August 06, 2015, 03:39:01 PM »
Some instructions have a max execution time of up to 600us, while the write cycle has a minimum of 500ns. For the LCD display it takes a max of 37us for some instructions.

NHD-0220DZW-AY5 Datasheet

350
OLEDs / Re: NHD‐0220DZW‐AY5 loosing columns
« on: August 06, 2015, 08:24:01 AM »
Hi,

This situation often occurs because of a timing error in the code, You mentioned you are using the same code as the NHD-0220GZ-FL-GBW, while they have the same commands, the OLED does require more time between instructions.

351
OLEDs / Re: NHD-0420CW-AB3 init / cgram
« on: August 06, 2015, 07:52:17 AM »
Glad to see  everything worked out.

352
OLEDs / Re: SPI Communication Start Byte
« on: August 05, 2015, 08:18:51 AM »
According to the datasheet you should be able to. The start byte dictates whether the following chain of instructions are commands or not.

353
OLEDs / Re: NHD-0420CW-AB3 init / cgram
« on: August 05, 2015, 08:15:44 AM »
One thing I've noticed and I'm not sure if you're doing it else where, the (0x00) you are sending for ROM selection should be sent as data and not a command. Same would be true when you are disabling the internal voltage regulator.

354
OLEDs / Re: NHD-0420CW-AB3 init / cgram
« on: August 04, 2015, 08:17:07 AM »
I was wondering if it would be possible to see your code specifically how you are writing either data or commands to the display. Also where you are selecting the ROM for custom characters..


355
OLEDs / Re: NHD-0420DZW-AY5 with scrambled display
« on: August 03, 2015, 10:31:13 AM »
Hi,

I was wondering what that WaitReady function?

I still suspect timing might be the issue.

For the Write LCD function you mention that the execution time for previous command is around 300us. In the Table of command it does mention that most of the commands do have a 600us max execution time.

356
OLEDs / Re: NHD-0420CW-AB3 init / cgram
« on: August 03, 2015, 10:18:40 AM »
That 0x72 followed by data 0x00, selects ROM A.

I was wondering if you could post the code of how you are accessing the CGROM to put a character in the memory; also how you are printing the character out.

Example for what I have done to load a custom character in is:
Code: [Select]
command(0x40);
  data(0x1F);
  data(0x15);
  data(0x15);
  data(0x04);
  data(0x04);
  data(0x15);
  data(0x15); 
  data(0x1F);


357
OLEDs / Re: NHD-0420DZW-AY5 with scrambled display
« on: July 31, 2015, 07:44:02 AM »
Would it be possible to take a look at the code you are using to initialize the LCD and write to it?

358
OLEDs / Re: NHD-0420DZW-AY5 with scrambled display
« on: July 30, 2015, 02:49:50 PM »
Hi,

From past experiences, it's usually a timing issue that causes strange characters to appear onto the display. This usually happens after the units have been running for a while. Usually when the timing commands are right on the threshold of the specifications.

I was wondering if you could tell me what interface you were using?

359
OLEDs / Re: SPI Communication Start Byte
« on: July 30, 2015, 11:05:12 AM »
You should be able to send continuous commands as well.

The minimum wait time should be about 40 ns. For the clock rise time, and the clock rise time plus hold time.

360
TFTs / Re: Controlling NHD-3.5-320240MF
« on: July 29, 2015, 08:04:28 AM »
The NV3035C is just the Driver, we do have controller boards specifically for this display. You can choose from either:

8-bit Parallel:   http://www.newhavendisplay.com/nhd35320240mf20-controller-board-p-2656.html
16-bit Parallel: http://www.newhavendisplay.com/nhd35320240mf34-controller-board-p-2675.html

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