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Topics - v8dave

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TFTs / NHD-7.0-1024600AF-LSXP-CTP timing information required
« on: August 27, 2019, 07:47:07 PM »
I have purchased some of the new 7" IPS TFT displays to test with and my interface to them is RGB from the processor and then converted to LVDS at the PCB fitted onto the rear of the LCD. This is the same design that my present LCD supplier uses but their display is low brightness but they don't have a 1024x600 option in the kernel.

In the datasheet for the NHD-7.0-1024600AF-LSXP-CTP, there is no timing information for the panel?

Does anyone have the timing values for this display?

It would be great if we could get a sunlight readable display with 1280 x 800 resolution and capacitive touch. I know this would need to be LVDS but that is not an issue with modern processors and or an RGB to LVDS IC board fitted to the back of the LCD panel.

TFTs / NHD-7.0-800480EF-ASXN#-CTP with Android Linux
« on: May 12, 2019, 10:08:39 PM »
I am trying to get a NHD-7.0-800480EF-ASXN#-CTP display working with Android and I am unable to get anything to display on the LCD. I've used this same LCD before with a small processor running .NET Microframework with great success, albeit a slow interface.

I am using the following timings and checking with a scope to ensure the wiring is correct, I do see the HSYNC, VSYNC, DEN and CLK on the correct pins.

static struct nxp_lcd wvga_axon = {
   .width = 800,
   .height = 480,
   .p_width = 155,
   .p_height = 93,
   .bpp = 24,
   .freq = 40,

   .timing = {
      .h_fp = 40,
      .h_bp = 88,
      .h_sw = 48,
      .v_fp = 13,
      .v_fpe = 1,
      .v_bp = 32,
      .v_bpe = 1,
      .v_sw = 3,
   .polarity = {
      .rise_vclk = 1,
      .inv_hsync = 1,
      .inv_vsync = 1,
      .inv_vden = 0,
   .gpio_init = nhd_gpio_init,

I've tried different settings for the polarity with no success. The kernel code has extra debug to confirm the LCD settings are being applied.

Anyone else been able to make this work?

Customer Projects / Clock and weather display
« on: July 11, 2017, 09:47:40 AM »
Using 2 of the 4.3" sunlight readable displays I built a display to show time and weather data.

The processors on both boards are GHI Electronics G120 with native LCD interface direct to the Newhaven LCD modules. Using .NET Microframework and C#, code for the clock and the weather was done in 1 app. The weather side has a WiFi module so this is used to auto detect which board is running and setup the display.

Additional to the weather screen is power and fridge/freezer temperatures.  ;)

The data itself is transmitted onto the network using MQTT protocol from a number of ESP8266 modules so the display simply listens for this data from the MQTT server.

Additional to the weather side is the local weather forecast from Weather Underground.

The enclosure was designed with 3D CAD software and then all front, rear and side panels made via the Front Panel Express service from Schaeffer-AG in Germany. Top quality for 1 off or small run projects. Not the cheapest option but the finished design is really good.

Customer Projects / Commercial design with 7" LCD
« on: May 02, 2016, 09:49:26 PM »
Using the NHD-7.0-800480EF-ATXV#-CTP display I built in-house, a commercial design for an international client to log data from a down hole gauge and communicate and control a Variable Speed Drive.

The Newhaven displays are excellent. They may not be the cheapest on the market compared to Chinese options but the support from Newhaven is second to none and the fact that all the voltages for the displays are generated within the LCD module makes the design simple as using 3.3V and the digital inputs. Quality is also top notch.

I have used the 4.3" and 5.0" displays in the past but decided to use the 7" on this unit to better fit the overall unit size.

The unit itself has a special interface that I designed to convert two 4-20mA sensors onto the one grounded cable. This allows me to have temperature and pressure in the well and at a price that makes it low cost enough to allow this client to instrument each well. Conventional downhole sensors are expensive. Using 4-20mA we can instrument wells down to 12,000 feet depth.

The rest of the system is standard 4-20mA inputs for surface pressure and temperature sensors and an optional storage tank calculation for one of the sensors.

The unit includes a 3G GSM modem to allow the well data to be transmitted to a server or via SMS. This modem can be offered in USA and International operating frequencies.

My only request to Newhaven for the future is to have a high brightness version of this display. Something along the lines of the 4.3" option would be great. :)

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TFTs / LCD timing signals
« on: January 12, 2015, 09:13:52 PM »
I am using an NHD-7.0-800480EF-ATXV display with a Allwinner A20 Cortex A7 processor and I am seeing some flickering and whiteouts on the display when I run on battery power and the battery voltage gets low. The voltage to the LCD is still close to 3.3V but any current increase from the board causes small dips in the supply and this affects the stability in the LCD.

The battery is 6600mA capacity and I think the issue with the LCD is due to the fact the board design uses a buck regulator for the 3.3V instead of a buck/boost so that it can still run when the input is close to 3.3V

NOW.. What I did find during all this checking was that the LCD clock output from the CPU is not a square wave as I was expecting, based on the information in the datasheets.

This image shows that the clock is actually a sine wave. Now, when I posted about this on another group, they said to check the scope bandwidth etc. Measuring the R,G and B lines, which are clocked in at the same rate as the DCLK, they have a nice 0 to 3.3V swing and square edges so I am confident that the bandwidth is not the issue here.

As you can see, the clock is not 0 to 3.3V but approx 1V to 1.8V swing. This clock is 33Mhz.

I also checked the output from an LPC1788 driving an LCD at 25Mhz and it shows the same type of output.

The issue I think is that the voltage levels are critical at lower voltages but not so sure until I can get confirmation that the clock output from the CPU is correct.

Does anyone know if what I am seeing is indeed correct? Even looking at the controller datasheet on the LCD shows a square type clock and the triggering voltages would not be met with this clock I am seeing.

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