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Character LCDs / NHD-C0220Biz-FS(RGB)-FBW-3VM initialization problem
« Last post by Chruetli on December 01, 2017, 02:40:04 PM »
I'm using an embedded Linux system - with a dedicated I2C bus - to drive a "NHD-C0220Biz-FS(RGB)-FBW-3VM" display. The Linux kernel module supplies an I2C master, so I do not have to bit bang.
Using 'i2c_master_send(...)' does the addressing, clocking and so on. Most calls work but 0x39 and 0x01 don't work...
0x0  -> ok
0x38 -> ok
0x39 -> fail
0x14 -> ok
0x0c -> ok
0x01 -> fail

I also tried to make 2 byte packets {0x0, 0x?} and send them together but the same commands failed. And there is no visible reaction on the display.
Any sugestins?
Accessories / Bezel for NHD-C0216CiZ-FSW-FBW-3V3
« Last post by LegacyOfHerot on November 27, 2017, 04:15:56 AM »
We want to use one of the above in a small case, is there a bezel either made by Newhaven, or a suitable one from a 3rd party? Ideally one with clear plastic display area, as your glass seems so easily affected by environment.
New Product Wishlists / Please use standard 2.54 mm Pin pitch
« Last post by LegacyOfHerot on November 24, 2017, 05:37:23 AM »
On the COG displays like NHD-C0216CiZ-FSW-FBW-3V3 the control / data pins are 1.5mm pitch (but the backlight pins are 2.54mm)
While its easy enough to make the pcb layout 1.5mm, for production test / prototyping, having a standard pitch of 2.54mm would make life so much easier, we could use cheap pcb headers.

I have used this display and the pinouts do confuse a few people.
However i can confirm that when you are looking at the front of the display the pin on the far right is the Reset pin.

The schematic on EasyEDA might be looking at the display from the back, would it be possible to link that to me?
Ok, for those that have used the NHD-C0220Biz-FS(RGB)-FBW-3VM I have a stupid question. My display is not working and I verified the STM32 code is correct and even probe all the i2c addresses and see my i/o expander but never the display. I was verifying everything and I initially thought it was odd the numbering on the LCD is 8..1 from left to right instead of 1..8. So, I have RST on the far right pin and C1- on the far left pin. I am thinking the manufacture documentation is wrong. I found a schematic symbol and matching footprint on EasyEDA for the same display and it has C1- on the far right (opposite from what the manf. documentation shows). Can someone verify the pin layout on this display?
Graphic LCDs / Can't get NHD-12232KZ to work with STM32
« Last post by pcbguy1 on November 18, 2017, 01:05:00 PM »

I purchased one of these displays for a project that I'm working on and it's proving to be difficult to get it to work nicely with an STM32. I'm using SPI to send the data to an 8-bit shift register whose outputs are routed to the LCD's data pins. I looked at the data sheet and confirmed the timing for a 3.3V system, and tried translating the example code given to the STM32, but to no avail. I tried the code in 6800 mode and in 8080 mode, and both produce no results.

I've confirmed that the hardware lines are functioning correctly and are routed to the correct positions, the shift register outputs the correct data, and the SPI transmission is correct. When the reset button is pressed, the LCD displays a single straight horizontal line, but when I let go of the reset button the line disappears. I double checked all grounds and they're fine.
Are there any details that I may have missed when initializing the LCD?
TFTs / Re: working with nhd-7.0-800480ef-asxv-t with buildroot framebuffer
« Last post by mnylund05 on November 17, 2017, 08:40:34 AM »
I am not getting any display activity, just blank screen.  I have configured panel-simple to all know parameters for this display and still nothing
Character LCDs / NHD-0420D3Z-FL-GBW-V3 backlight flicker
« Last post by ThomyLanty on November 17, 2017, 04:39:52 AM »
I'm using a NHD-0420D3Z-FL-GBW-V3 in SPI mode at 64kHz. All functions are working, but the backlight is flickering randomly.

I figured out that the PIC16 microcontroller that sits on the display PCB is dimming the backlight by PWM. I measured this PWM pin and I saw that it is skipping a cycle once in a while, which causes the flickering.
Then I measured the SPI lines simultaneously and I saw that the missing PWM cycle always occurs short after the end of a SPI write cycle, short after the CS pin getting high.
See the attached screenshots of the timing (Ch 4 is the SPI MOSI instead of CH3).

As far as I can tell I met all timing constraints. It looks like the PIC 16 controller can't keep up and first handles the SPI transfer and then misses the timing of the PWM. SPI will probably have a higher priority then PWM.

Does anyone have an idea to fix this issue?
TFTs / Re: working with nhd-7.0-800480ef-asxv-t with buildroot framebuffer
« Last post by Saurabh_B on November 16, 2017, 08:15:38 AM »
Can you give us more information as to what issues you are having?
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