1 1
James Kingdon

Cheap HDMI monitor -1

Recommended Posts

Hi,

 

I noticed OrangePi have started selling a 7" lcd with an hdmi adapter. It's only 1000x600 (which might be an awkward resolution to get working with some SBCs) but I thought I'd give one a try. This might fit into my farm build as a dedicated status monitor or something :)

It's 22 usd plus shipping:

https://www.aliexpress.com/item/7inch-TFT-LCD-Screen-for-Orange-Pi-H3-chip-Boards/32831758014.html

Share this post


Link to post
Share on other sites
8 hours ago, pzw said:

it states 1024x600

it looks like, in the feedback of Aliexpress a person from Japan says so.

 

I would love to have a 7" screen with touch and - a holder for the display . So is it possible to put a touch-layer on top of that so I could build a music-player and such?

Last but not least for a reasonable price.

Share this post


Link to post
Share on other sites
7 hours ago, Tido said:

So is it possible to put a touch-layer on top of that so I could build a music-player and such?

Sounds like an interesting project, but I suspect it would be a lot easier to buy a combined screeen and touch panel rather than try and put something together yourself.

Share this post


Link to post
Share on other sites

I don't get it, why they advertize it as suitable for H3 boards? H5 boards cannot speak LCD/HDMI or what? :D

Interesting thingy, definitely, probably I'll buy it someday. But now I have a 21" HDMI capable monitor bought specifically for my "playing" with SBCs. :)

Share this post


Link to post
Share on other sites

It arrived yesterday, having taken about two weeks. That's far quicker than previous orders from OrangePi which have taken between two and three months. I hope that's a change that sticks! I hooked the LCD up to my laptop for a quick test and immediately ran into the oddball resolution issue - the laptop doesn't have a setting for 1024x600. The LCD will have a go at sinking to pretty much any signal you send it, but some are more readable than others. 800x600 worked well enough to easily read text in a terminal and play youtube videos. The screen looks pretty good for the price, nice and bright, good colours, but with a pretty narrow viewing angle.  As long as I can get a usable resolution out of one of the SBCs it should make a nice status monitor.

Share this post


Link to post
Share on other sites
6 hours ago, James Kingdon said:

It arrived yesterday, having taken about two weeks. That's far quicker than previous orders from OrangePi which have taken between two and three months. I hope that's a change that sticks!

 

I ordered only a few times from Xunlong (late 2015, early 2016) and the stuff always arrived within 2 weeks.

 

6 hours ago, James Kingdon said:

the laptop doesn't have a setting for 1024x600

 

I dealt with a similar HDMI display years ago and had to figure out fbset settings myself back then: https://www.cnx-software.com/2017/09/15/7-lcd-display-with-hdmi-input-audio-output-launched-for-orange-pi-boards/#comment-546014 -- would be interesting whether the display provides correct EDID data so at least with mainline kernel and the new HDMI driver @jernej wrote there's a chance using the display's native resolution with some SBC.

Share this post


Link to post
Share on other sites

Ok, I grabbed the edid info, but it's clearly bogus, or at least reflects what the chip can do rather than the lcd. Sadly, none of the listed modes are a good match for the lcd.

 

Section "Monitor"
	Identifier "LONTIUM"
	ModelName "LONTIUM"
	VendorName "LTM"
	# Monitor Manufactured week 46 of 2010
	# EDID version 1.3
	# Digital Display
	DisplaySize 890 500
	Gamma 2.20
	Option "DPMS" "false"
	Horizsync 26-81
	VertRefresh 24-75
	# Maximum pixel clock is 230MHz
	#Not giving standard mode: 1152x864, 60Hz
	#Not giving standard mode: 1280x800, 60Hz
	#Not giving standard mode: 1280x960, 60Hz
	#Not giving standard mode: 1280x1024, 60Hz
	#Not giving standard mode: 1440x900, 60Hz
	#Not giving standard mode: 1400x1050, 60Hz
	#Not giving standard mode: 1600x1200, 60Hz
	#Not giving standard mode: 1680x1050, 60Hz

	#Extension block found. Parsing...
	Modeline 	"Mode 10" 79.50 1280 1344 1472 1664 768 771 778 798 -hsync +vsync 
	Modeline 	"Mode 0" 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync 
	Modeline 	"Mode 1" 85.50 1360 1424 1536 1792 768 771 777 795 +hsync +vsync 
	Modeline 	"Mode 2" 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
	Modeline 	"Mode 3" 148.500 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
	Modeline 	"Mode 4" 74.250 1280 1390 1420 1650 720 725 730 750 +hsync +vsync
	Modeline 	"Mode 5" 74.250 1280 1720 1760 1980 720 725 730 750 +hsync +vsync
	Modeline 	"Mode 6" 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
	Modeline 	"Mode 7" 27.000 720 732 796 864 576 581 586 625 -hsync -vsync
	Modeline 	"Mode 8" 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
	Modeline 	"Mode 9" 27.000 720 732 796 864 576 581 586 625 -hsync -vsync
	Modeline 	"Mode 11" 85.50 1366 1436 1579 1792 768 771 774 798 +hsync +vsync 
	Modeline 	"Mode 12" 100.00 1600 1648 1680 1780 900 903 909 936 +hsync +vsync 
	Modeline 	"Mode 13" 74.25 1280 1390 1430 1650 720 725 730 746 +hsync +vsync 
	Option "PreferredMode" "Mode 10"
EndSection

 

Share this post


Link to post
Share on other sites

If you learn Mandarin, you might be able to find some documentation on the LT8619B chip on the converter board that will tell you how to program it to correctly configure the EDID data.

All I could find was product briefs and marketing info

 

And this, which may be source for the the MCU built in to the LT8619 http://en.pudn.com/Download/item/id/3217232.html but I have no idea really.

Share this post


Link to post
Share on other sites
On 16.10.2017 at 12:51 AM, James Kingdon said:

it would be a lot easier to buy a combined screeen and touch panel

A valid point - and I found two, one I couldn't find anymore returned and the other from 52pi finally have the capacitive touch-screen.

 

WSVGA = 1024 x 600  |  ~17:10

 

7“ Capacitive Touch LCD (D) 1024 x 600, module RGB and LVDS Interface FT5206GE1 TouchController IC (MarsBoard HY070CTP-HD) - connection: 40-pin FFC × 1  --> which might limit your options on SBC with that kind of connector. $ 47,51.-

 

7“ Capacitive Touch LCD with an external driver board for Touch and one for the Display $ 49,79.-. If I am not wrong you can also mount it on their Holder $ 10,99.-.

 

As the latter offers more flexibility with regard to connectors, I guess I will order that one.


FT = FocalTech Systems Co. Ltd.

FT5206 < 3,7“

FT5406 < 7,0“


These were the specification for the Pi Display

  • RGB 800×480 display @60fps
  • 24-bit colour
  • FT5406 - 10 point capacitive touch panel controller
  • 70 degree viewing angle

 

Edited by Tido
added WSVGA

Share this post


Link to post
Share on other sites
11 hours ago, James Kingdon said:

Ok, I grabbed the edid info, but it's clearly bogus

 

As expected :( -- thanks for confirming. But I think I already learnt my lesson back in 2015 to not try to use ever again a HDMI attached display with exotic native resolution (if the device to attach to is not a Raspberry where it's easy to configure/use 1024x600 unlike almost everywhere else)

Share this post


Link to post
Share on other sites

WSVGA = 1024 x 600  |  ~17:10

I saw a little movie where the Display was running attached to a BeagleBone.

 

Somone posted this in our forum May 2016:

Table of Displayresolutions, Formatname, Ratio and Pixelcount:

WSVGA Wide SVGA 1024 × 600 ≈ 17:10 16∶9 1.041 614.400   WSVGA Wide SVGA 1072 × 600 ≈ 16:9 16∶9 0.995 643.200

 

At the bottom of his Blog post he added: A relevant newbie thread about this can be found here…

it might be worth mentioning that he uses either 800x480 or 800x600

Share this post


Link to post
Share on other sites

A silly question, but I never had experience in HDMI controller programming. I found out that the board I work on, doesn't document an HDMI controller it uses. But it is similar to that iMX6 has and what alwinner SoCs have, something synopsys designware hdmi transmitter something.

Maybe here are people having such an expereince, I am sure they are, my question:

does this transmitter need a cooperation with SoC LCD controllers? Or writing some kind of framebuffer support for drawing hdmi display, one doesn't need LCD controllers? this question arises because the vendor crappual describing LCD mentiones once "support for hdmi". this mess leaves no chance for a beginner to get it. I know the answer is lying somewhere inside the BSP code, but before I dig into that horrid mess, with bloat-code like this

and very instructive comments:


/* calculate teh fast sped high time counter - round up */

some clarifications would be so much appreciated!

Does one need to program LCD controllers as well as hdmi transmitter in order to draw on an hdmi display?

Share this post


Link to post
Share on other sites

@valant

I can give you some help since I'm working on Allwinner DW-HDMI implementation, but what you asking is totally platform dependant. At least on Allwinner, LCD controller (called TCON) is just something which outputs raw data on parallel or LVDS interface. If you want anything else (TV, HDMI, MIPI-DSI) you must chose pipeline which has encoder right behind LCD controller. So it looks something like:

 

LCD:

Display Engine (HW composer) -> TCON (LCD controller) -> LCD panel

 

HDMI:

Display Engine -> TCON -> HDMI

 

I took a quick look at your BSP code and it seems that you have same situation. That means that LCD controller needs to be enabled and properly set up in order to use HDMI.

 

If you are writing driver for mainline kernel or U-Boot, you are fortunate that most heavy lifting is already done for DW HDMI. You just use library provided inside. If your SoC uses Synopsys PHY, you just need to provide few numbers extracted from BSP driver and some boilerplate code. Unfortunatelly, you have to write full DRM driver for, I'm not sure how there is called, Display Engine and/or (only?) LCD controller.

Share this post


Link to post
Share on other sites

thank you, jernej.

no this is not for the linux kernel, for it, they do (did) something "mainline" (which means 3.18).

 

still it's too hard to understand the underlying HDMI things from there. I have to either consult with DW bsp for the older kernel or the mainline DRM thing made by freescale. which is called:



Synopsys DWC HDMI TX Controller and TX Phy driver modeled as drm encoder

is this that thing you mentioned? they seem to have rewritten the low level code.

 

both options unfortunately aren't the  straightest way to get an idea on hdmi programming. the first is sooo bloated and the coding style is just killing me, like it is something automatically generated from C++. xD in the second, as expected - too many distracting irrelevant things around. I am just sinking in linux internals. whereas I need to only a normal description of how to program an HDMI controller. but there is hope to get yet a little of understanding from the iMX6 manual.

 

What I need is a basic support of the hdmi output for the FW UI, that ugly BIOS-like interface, nothing more at first.

 

and thank you for your suggestuion to help. I'll try to not abuse it. :)

Share this post


Link to post
Share on other sites

@valant

 

Yeah, I mean that, but if I understand you correctly, you need just a basic (static?) setup, without any bells and whistels. Then you should probably check U-Boot implementation located here. It is much more basic and it can be reduced even further if you remove audio related stuff. If you want to support only one predefined resolution, then you could also remove all DDC/EDID related stuff. Both changes will probably leave you with only half of the code. I think this is really bare minimum for DW HDMI.

 

i.MX6 documentation should suffice for such setup. You can even find original pre-release version of DW HDMI documentation on some Chinese forum (I don't know which), but as I said, i.MX6 doc is enough for probably everything you need.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
1 1