I have been trying to figure out how exactly the RGB interface that the eoma-68 standard supplies works. Or, in other words, what you would need to be able to connect it to a screen. The info that I have managed to find makes me think this would connect directly to a LCD or TTF screen's ribbon cable. Is there a description of what is provided with this interface somewhere?
--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Sun, Aug 28, 2016 at 3:42 AM, Louis Pearson desttinghimgame@gmail.com wrote:
I have been trying to figure out how exactly the RGB interface that the eoma-68 standard supplies works. Or, in other words, what you would need to be able to connect it to a screen. The info that I have managed to find makes me think this would connect directly to a LCD or TTF screen's ribbon cable.
correct. TFT not TTF.
Is there a description of what is provided with this interface somewhere?
RGB/TTL. that's all that's needed to be known. watch out for the fact that it has a reference voltage VREFTTL.
l.
Most TFT screens of relevance here use LVDS, which is entirely different... TTL as implemented is a parallel 8bit/color scheme IIRC, whereas LVDS is serial and involves both positive and negative voltages... you'll blow up the controller in the LCD panel if you hook one to the other.
So a conversion from TTL to LVDS needs to be done in most cases?
On Sun, Aug 28, 2016, 10:23 Christopher Havel laserhawk64@gmail.com wrote:
Most TFT screens of relevance here use LVDS, which is entirely different... TTL as implemented is a parallel 8bit/color scheme IIRC, whereas LVDS is serial and involves both positive and negative voltages... you'll blow up the controller in the LCD panel if you hook one to the other. _______________________________________________ arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netbook@files.phcomp.co.uk
Almost all. I can't really help with that -- there should be some sort of controller or interface chip/circuit there, but that's all I know. I've not learned much of that sort of stuff yet.
I will say that I once had a TTL LCD panel, 9in diagonal IIRC -- but it was very strange in a number of other respects in addition to protocol. I'd gotten it from eBay, and it arrived a bare LCD -- by which I mean that it was *just* the panel and control circuitry. You could see right through it -- I was to provide my own backing for it, and backlight as well! Plus the connector was an odd number of pins -- no key pin, longer on one side than the other. Weird, weird surface mount thing. Not having any use for it, I recycled the panel and wrote off the (fortunately fairly minimal) expense.
'Twas a Sharp panel, as I recall. I may still have the datasheet -- I'm making some adjustments after installing Linux Mint right now on the machine that would have that document. I'll look when it's done... should be a half hour or so. Who knows? Maybe it comes with backing and backlight now... if not, it's still possibly useful if you throw it on an overhead projector (remember those? :D ) -- I've seen that exact use case in school, years ago... it's doable. I don't know if it screws with the panel, though...
On Sun, Aug 28, 2016 at 4:59 PM, Louis Pearson desttinghimgame@gmail.com wrote:
So a conversion from TTL to LVDS needs to be done in most cases?
no - a conversion from RGB/TTL to LVDS (e.g. using a SN75LVDS83b) is needed on a *specific* case-by-case basis, depending on what LCD you want to use.
clearly and obviously you would not convert from RGB/TTL to LVDS in order to connect to a MIPI LCD - you would use an SSD2828 for that.
you would clearly and obviously not convert to LVDS to connect to an eDP panel.
you need to use common sense here.
l.
@Luke -- wouldn't most LCDs of the sort we're discussing be LVDS, eg "donated" from an otherwise-dead laptop...?
True that there are other protocols in use, though...
--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Sun, Aug 28, 2016 at 5:41 PM, Christopher Havel laserhawk64@gmail.com wrote:
@Luke -- wouldn't most LCDs of the sort we're discussing be LVDS, eg "donated" from an otherwise-dead laptop...?
not necessarily. a modern one witll be eDP. it might be MIPI but that's unlikely. depending on resolution and age it'll be single, dual or triple LVDS.
it's literally impossible to know until you either search online or open up the back (dismantle the laptop) and get the make / model of the LCD.
l.
On Sun, Aug 28, 2016 at 12:53 PM, Luke Kenneth Casson Leighton < lkcl@lkcl.net> wrote:
it's literally impossible to know until you either search online or open up the back (dismantle the laptop) and get the make / model of the LCD.
That's true. I'd still argue that, unless it has the shape of a certain fruit on the other side of the lid ;) the panel inside is gonna be LVDS. I fully admit to talking out my rear on that one, tho...
--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Sun, Aug 28, 2016 at 5:56 PM, Christopher Havel laserhawk64@gmail.com wrote:
On Sun, Aug 28, 2016 at 12:53 PM, Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
it's literally impossible to know until you either search online or open up the back (dismantle the laptop) and get the make / model of the LCD.
That's true. I'd still argue that, unless it has the shape of a certain fruit on the other side of the lid ;) the panel inside is gonna be LVDS. I fully admit to talking out my rear on that one, tho...
http://support.hp.com/in-en/document/c04913012
eDP
https://www.amazon.com/PROBOOK-Replacement-Screen-Laptop-Matte/dp/B017A5X0Y0
eDP
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Well, then. I have been corrected.
Fun fact: all you need to hook an eDP display up to any computer with a DisplayPort output -- is a cable that adapts the connectors to each other. Someone on Hackaday did that a year or two ago. I thought it was neat then and I still do... don't think I bookmarked it tho.
Thanks for ask these replies! I'm pretty new to displays do this has been very informative. For the project in working on, I'll be using a smaller screen, maybe with a touch screen. Something like this:
http://m.ebay.com/itm/161863547262?_trkparms=aid=222007&algo=SIC.MBE&...
According to the page it accepts an 8-bit signal. From the looks of it, this would be able to directly use the RGB/TTL signal.
Another question I have is about SPI based displays. There seems to be a lot in this size range. Would those be able to display hardware accelerated video? Is that even a concern with this small of a display?
On Sun, Aug 28, 2016, 12:02 Christopher Havel laserhawk64@gmail.com wrote:
Well, then. I have been corrected.
Fun fact: all you need to hook an eDP display up to any computer with a DisplayPort output -- is a cable that adapts the connectors to each other. Someone on Hackaday did that a year or two ago. I thought it was neat then and I still do... don't think I bookmarked it tho. _______________________________________________ arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netbook@files.phcomp.co.uk
That's not RGB/TTL... that's parallel 8-bit. Different ball game. RGB/TTL is either 24-bit (8 bits per color) or 16 bit (6 bits red / 6 bits green / 4 bits blue -- blue is more intense to the human eye so it only *needs* four bits vs six for another color). The thing you're talking about... that gets talked to more like a character LCD than anything else. You know the display on those old HP laser printers you used in grade school? The ones that could *only* display text, and had a dedicated spot for each character...? *That's* a character LCD. *That's* the kind of interface you're looking at here.
Dude, if all you're driving is that kinda thing... use an Arduino. If you absolutely need Web connectivity (or if you need a little number-crunching ability but not a lot), use an ESP8266. On that note -- a friend of mine has found a way to turn off an ESP8266's WiFi side if you don't need it. (Info here. http://www.hackster.io/rayburne/esp8266-turn-off-wifi-reduce-current-big-time-1df8ae) If you somehow need something that's more than a fractional-horsepower driver for it ;) like if you're building some kinda fancy pants Johnny Five robot... throw a RasPi at it.
Here, this might provide some inspiration --> http://johan.kanflo.com/ the-commadorable-64/ Despite the name, it's a daughterboard for a display like yours, that integrates an ESP8266 and driver circuitry. You'd have to buy the parts and solder it together -- and it's almost all surface mount stuff, mind you, which is a real pain in the tail... but it's worth it from what I can see here.
EOMA68 is *way* overpowered for any application using that kind of display. EOMA68 is on the level of a Dell desktop, or at least an older ASUS netbook.
On Sun, Aug 28, 2016 at 2:01 PM, Louis Pearson desttinghimgame@gmail.com wrote:
Thanks for ask these replies! I'm pretty new to displays do this has been very informative. For the project in working on, I'll be using a smaller screen, maybe with a touch screen. Something like this:
http://m.ebay.com/itm/161863547262?_trkparms=aid= 222007&algo=SIC.MBE&ao=1&asc=20150831081539&need= 62b51881f4054df6a178d0b1ebe1038d&pid=100518&rk=4&rkt=25&sd= 262136737363&_trksid=p2349624.c100518.m4111&_mwBanner=1
According to the page it accepts an 8-bit signal. From the looks of it, this would be able to directly use the RGB/TTL signal.
Another question I have is about SPI based displays. There seems to be a lot in this size range. Would those be able to display hardware accelerated video? Is that even a concern with this small of a display?
On Sun, Aug 28, 2016, 12:02 Christopher Havel laserhawk64@gmail.com wrote:
Well, then. I have been corrected.
Fun fact: all you need to hook an eDP display up to any computer with a DisplayPort output -- is a cable that adapts the connectors to each other. Someone on Hackaday did that a year or two ago. I thought it was neat then and I still do... don't think I bookmarked it tho. _______________________________________________ arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netbook@files.phcomp.co.uk
arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netbook@files.phcomp.co.uk
The "project" I'm doing is mostly about learning some new skills, it is a personal project that I'm doing on the side. It would be a handheld game console, mostly for GB or NES emulation.
So I guess a Raspberry Pi would be a better target, but... well, I rather like the idea of EOMA-68. My concept would be similar to the handheld ZEOMA console, but more reminiscent of the GameBoy. The benefit of using the EOMA-68 would be the ability to transfer your games between devices very easily.
Eh, maybe it's not the greatest idea. I could just use a raspberry pi and it would work mostly the same.
Thanks for the help anyway.
On Sun, Aug 28, 2016, 13:17 Christopher Havel laserhawk64@gmail.com wrote:
That's not RGB/TTL... that's parallel 8-bit. Different ball game. RGB/TTL is either 24-bit (8 bits per color) or 16 bit (6 bits red / 6 bits green / 4 bits blue -- blue is more intense to the human eye so it only *needs* four bits vs six for another color). The thing you're talking about... that gets talked to more like a character LCD than anything else. You know the display on those old HP laser printers you used in grade school? The ones that could *only* display text, and had a dedicated spot for each character...? *That's* a character LCD. *That's* the kind of interface you're looking at here.
Dude, if all you're driving is that kinda thing... use an Arduino. If you absolutely need Web connectivity (or if you need a little number-crunching ability but not a lot), use an ESP8266. On that note -- a friend of mine has found a way to turn off an ESP8266's WiFi side if you don't need it. (Info here. http://www.hackster.io/rayburne/esp8266-turn-off-wifi-reduce-current-big-time-1df8ae) If you somehow need something that's more than a fractional-horsepower driver for it ;) like if you're building some kinda fancy pants Johnny Five robot... throw a RasPi at it.
Here, this might provide some inspiration --> http://johan.kanflo.com/the-commadorable-64/ Despite the name, it's a daughterboard for a display like yours, that integrates an ESP8266 and driver circuitry. You'd have to buy the parts and solder it together -- and it's almost all surface mount stuff, mind you, which is a real pain in the tail... but it's worth it from what I can see here.
EOMA68 is *way* overpowered for any application using that kind of display. EOMA68 is on the level of a Dell desktop, or at least an older ASUS netbook.
On Sun, Aug 28, 2016 at 2:01 PM, Louis Pearson desttinghimgame@gmail.com wrote:
Thanks for ask these replies! I'm pretty new to displays do this has been very informative. For the project in working on, I'll be using a smaller screen, maybe with a touch screen. Something like this:
http://m.ebay.com/itm/161863547262?_trkparms=aid=222007&algo=SIC.MBE&...
According to the page it accepts an 8-bit signal. From the looks of it, this would be able to directly use the RGB/TTL signal.
Another question I have is about SPI based displays. There seems to be a lot in this size range. Would those be able to display hardware accelerated video? Is that even a concern with this small of a display?
On Sun, Aug 28, 2016, 12:02 Christopher Havel laserhawk64@gmail.com wrote:
Well, then. I have been corrected.
Fun fact: all you need to hook an eDP display up to any computer with a DisplayPort output -- is a cable that adapts the connectors to each other. Someone on Hackaday did that a year or two ago. I thought it was neat then and I still do... don't think I bookmarked it tho. _______________________________________________ arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netbook@files.phcomp.co.uk
arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netbook@files.phcomp.co.uk
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--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Sun, Aug 28, 2016 at 7:59 PM, Louis Pearson desttinghimgame@gmail.com wrote:
The "project" I'm doing is mostly about learning some new skills, it is a personal project that I'm doing on the side. It would be a handheld game console, mostly for GB or NES emulation.
So I guess a Raspberry Pi would be a better target,
not really.
but... well, I rather like the idea of EOMA-68. My concept would be similar to the handheld ZEOMA console, but more reminiscent of the GameBoy. The benefit of using the EOMA-68 would be the ability to transfer your games between devices very easily.
exactly. and future upgradeability to faster processors... without the effort of having to do a total redesign of the base console.
this is why manuel decided to base the hand-held console around EOMA68.
Eh, maybe it's not the greatest idea. I could just use a raspberry pi and it would work mostly the same.
you'll still have exactly the same issues if you use a raspberry pi. you'll still need to track down a suitable LCD. you'll still have to work out the interface interoperability.
read these build instructions and tell me if you think it's a good idea:
http://makezine.com/projects/build-raspberry-pi-powered-linux-laptop-that-fi...
l.
--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Sun, Aug 28, 2016 at 7:01 PM, Louis Pearson desttinghimgame@gmail.com wrote:
Thanks for ask these replies! I'm pretty new to displays do this has been very informative. For the project in working on, I'll be using a smaller screen, maybe with a touch screen. Something like this:
http://m.ebay.com/itm/161863547262?_trkparms=aid=222007&algo=SIC.MBE&...
According to the page it accepts an 8-bit signal. From the looks of it, this would be able to directly use the RGB/TTL signal.
nope - as chris points out, that's a "MCU" style interface (similar to the old IBM XT bus). 8-bit data/address, 1 line to say "it's address or data", 1 bit to say "it's read or write" and another for "clock".
you _could_ use it... you'd have to track down the datasheet for the controller IC.
basically.... welcome to my world! now you see why the project's taken 5 years! you've been on this for 2 days and you're tracking down just *one* of the components - the LCD! now you also have to find a trusted supplier...
Another question I have is about SPI based displays. There seems to be a lot in this size range.
yes.. because the controller ICs are extremely low-cost.
Would those be able to display hardware accelerated video?
not a snowball in hell's chance. 25mbit/sec *serial* data transfer - you can do the maths.
Is that even a concern with this small of a display?
try to find a video of the Adafruit HX8357D SPI-based LCD, you'll see that the drawing rate is veeery slow.
l.
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Christopher Havel -
Louis Pearson -
Luke Kenneth Casson Leighton