Can I connect a touch screen LCD to the Propeller Education Kit?

thean

Hi,

I am totally new to this world, and feeling very small among the giants...

I have the Propeller Education Kit (40 pin DIP) and looking to prototype an application that support a LCD touch screen and a number of switches and LEDs. Can I get a LCD touch screen, like the one designed by Rayman that is sold on Gatget Gangster ( http://www.gadgetgangster.com/find-a-project/56.html?projectnum=232 ) and connect it to the breadboard on the Propeller Education Kit?

Are there other choices (although i think Rayman's module is very reasonably priced if i can get it to work)?

What parts do I need and would appreciate detailed instructions, please?

Thanks.

MagIO2

As stated in the LCD product description you can also use the LCD with a breadboard. It includes a so called breakout-board. So, the PCB you see on the second picture at gadgetgangster also belongs to the LCD. You only have to solder the pin headers.

I think it's a matter of what you want to do with it. If you have a TV or VGA monitor you can first attach your propeller to that. You only need some resistors. As far as I remember the graphics you get with that LCD can be compared to what you get by TV or VGA. So, it won't be full color graphics and you can not display full resolution photos in full color with it.
If you are fine with that ... well ... fine, buy it.

Another way would be a 3,5" LCD with touchscreen which has it's own display memory. Together with an SD card you can have a nice GUI. Maybe I'll add a link to TRIPs posts later if I found it. He has a board with such a LCD display. I got a similar one from Crystalfontz and it's running on a breadboard as well.

thean

MagIO2 wrote: »

As stated in the LCD product description you can also use the LCD with a breadboard. It includes a so called breakout-board. So, the PCB you see on the second picture at gadgetgangster also belongs to the LCD. You only have to solder the pin headers.

I think it's a matter of what you want to do with it. If you have a TV or VGA monitor you can first attach your propeller to that. You only need some resistors. As far as I remember the graphics you get with that LCD can be compared to what you get by TV or VGA. So, it won't be full color graphics and you can not display full resolution photos in full color with it.
If you are fine with that ... well ... fine, buy it.

Another way would be a 3,5" LCD with touchscreen which has it's own display memory. Together with an SD card you can have a nice GUI. Maybe I'll add a link to TRIPs posts later if I found it. He has a board with such a LCD display. I got a similar one from Crystalfontz and it's running on a breadboard as well.

thean

Thanks MagIO2 for your reply.
Currently I do not need to display full color or very nice graphic for my application - although now that you've mentioned it, i should consider that posibilitty as an option for a more advanced future version. Which display did you get from Crystalfontz and can you give me some info about it (costing, and how you connect it to the breadboard), please?

MagIO2

I use this one:
http://www.crystalfontz.com/product/CFAF240320KTTS.html
You can see it here:
http://forums.parallax.com/showthread.php?117190-SPFD5408B-display-driver-(320x240x18)

The biggest crystalfontz is this:
http://www.crystalfontz.com/product/CFAF320240FTTS.html

Tripp sells complete boards:
http://forums.parallax.com/showthread.php?128236-Proppad-LCDboard-now-100Mhz-flicker-free-flying-3D-faster-image-loading-and-more&p=963639#post963639

Cluso99

thean: Welcome to the fantastic world of the propeller and this forum. Rayman has other options too. I have not done much work here so will leave it to others to advise.

thean

MagIO2, I am totally intimidated by all the wiring shown in the video of your project - it looks cool though.
I've decided to take a plunge with Rayman's touch screen module, at least as a first step - too hard at the moment to consider best/optimum solutions when i am totally new at everything. Think I need to get my feet wet first. When the unit arrives and I don't know what to do with it hope you don't mind giving some more help.

thean

Cluso99 wrote: »

thean: Welcome to the fantastic world of the propeller and this forum. Rayman has other options too. I have not done much work here so will leave it to others to advise.

Thanks Cluso99 for your welcome note.

MagIO2

The wiring is not that hard. It's only a data-bus of 8 wires and a hand full of controlling lines. And for Rays LCD you need some wiring as well. It's designed for the Gadgedgangster Propeller Platform and not for the PEKit breadboard. On the GPP all propeller IO pins are side by side whereas the propeller pinout has some pins (power supply, chrystal ...) in between pins 7 & 8 and 23 & 24.

But anyway ... I'm not here for selling something and I'm not fixed to any product, I only wanted to share the pros and cons I see for the different LCDs. Of course whatever your decision is you will get help.

The propeller font is nice for building buttons in text-mode which consumes less RAM than the graphics driver. If you need graphics it depends on the other things you have to do in your project. There are alternative graphics drivers which don't use double buffering, so you have some more RAM for your application.

thean

Hi MagIO2,

It's been a while and I have done some development in other areas of my project - now time to get back to the LCD touch screen. I need help getting this up and going sooner with some help rather than later working everything out on my own - and your reply to my initial message was very helpful already. Would you be interested in some commision work to help me set up a touch screen LCD module going (crystalfontz, 4.3 inch)? Please email: cmnguyen2000@hotmail.com - hope to get a reply from you soon.

Thean

MagIO2 wrote: »

As stated in the LCD product description you can also use the LCD with a breadboard. It includes a so called breakout-board. So, the PCB you see on the second picture at gadgetgangster also belongs to the LCD. You only have to solder the pin headers.

I think it's a matter of what you want to do with it. If you have a TV or VGA monitor you can first attach your propeller to that. You only need some resistors. As far as I remember the graphics you get with that LCD can be compared to what you get by TV or VGA. So, it won't be full color graphics and you can not display full resolution photos in full color with it.
If you are fine with that ... well ... fine, buy it.

Another way would be a 3,5" LCD with touchscreen which has it's own display memory. Together with an SD card you can have a nice GUI. Maybe I'll add a link to TRIPs posts later if I found it. He has a board with such a LCD display. I got a similar one from Crystalfontz and it's running on a breadboard as well.

HShanko

thean, welcome to the Propeller and this forum. You should find all sorts of help and education here.

I used Rayman's 3.5" touchscreen LCD and his board for it. Here's a bit of a look at it.

Using just 4 colors provided me with most of what I wanted. The 'case' is of a dense cardboard from a product's box. Quick and really cheap; just something to keep it one piece and not look totally shabby. Using 4 AA cells, it still runs on the first charge on them after a year.

MVC-073S.JPG

I use touch points to vary brightness, selecting number of samples, Hold/Run, and a debug feature to display or not various variables.. Also to select cursors to measure time between events. I used a simulated heart pulse waveform into a sigma-delta A/D to capture the signal with scaling. Actual front end to sense a real pulse is yet on the 'drawing board'.

Source code available if you wish to study/use

Rayman

That's really cool Harley! Thanks for posting that.

thean

Thanks Harley,

I actually did purchase Rayman's unit to play with - get my feet wet so to speak. But i am concerned about the supply in case the project i am working on is successful and a substantial production run is required. That's why i had to shop around for something that is likely to be available in reasonable quantity over the next several years.

Thean

HShanko wrote: »

thean, welcome to the Propeller and this forum. You should find all sorts of help and education here.

I used Rayman's 3.5" touchscreen LCD and his board for it. Here's a bit of a look at it.

Using just 4 colors provided me with most of what I wanted. The 'case' is of a dense cardboard from a product's box. Quick and really cheap; just something to keep it one piece and not look totally shabby. Using 4 AA cells, it still runs on the first charge on them after a year.

MVC-073S.JPG

I use touch points to vary brightness, selecting number of samples, Hold/Run, and a debug feature to display or not various variables.. Also to select cursors to measure time between events. I used a simulated heart pulse waveform into a sigma-delta A/D to capture the signal with scaling. Actual front end to sense a real pulse is yet on the 'drawing board'.

Source code available if you wish to study/use

Rayman

I can understand that concern. But, you can find other 4.3" and 3.5" displays that work the same as mine, just a different connector.
I think my 3.5" displays are still available from the manufacturer.

For 4.3" screens, I'd recommend either the ones that wjsteele used in his commercial product "Wingman" or the PSP screens.
Actually, there are a lot of choices and they all pretty much work the same way...

MagIO2

@thean: Welcome back to this thread ;o)

well ... I think you gave us to little information about your project for providing good tips.

Do you want graphics or text-only output? How many colors would you like to have? What other tasks are there for the propeller and how much RAM do you need for that? How many I/Os do you need for the other hardware you need to add? What size should the display have?

thean

Thanks Rayman for the info. I bought your 4.3" display with the break out board, and i understand that it was used, not new, hence concern about availability and quality. Now i see that you also have the 3.5" screen, new, and that is the one you said is still available from the manufacturer, do you also have the breakout board for that, or is it the same as the breakout board for the 4.3" display? If I change between the displays do I also have to change driver as well?

Rayman wrote: »

I can understand that concern. But, you can find other 4.3" and 3.5" displays that work the same as mine, just a different connector.
I think my 3.5" displays are still available from the manufacturer.

For 4.3" screens, I'd recommend either the ones that wjsteele used in his commercial product "Wingman" or the PSP screens.
Actually, there are a lot of choices and they all pretty much work the same way...

Rayman

thean, Unfortunately, although the connectors are identical, the pinout is completely different. Also, the 3.5" unit has two different modes (sync and DE).
I've now started selling a new breakout board for the 3.5" screen called "PTP2". I've posted about it recently, but it's not on my website yet...

It should be a lot better for breadboard setups because all the pins you need to wire up are all in one row...

thean

Hi MagIO2,
You are right - I did not give enough info - i thought people can read my mind, :-)
This is not a photo display application, so don't need all the color shades, although having enough color and resoluttion would help to create professional looking screen.

The display will be used to take user input (touch) : changing application options (picking from a list), difficulty levels, etc., possibly entering some numeric values (could be done with up/down arrows for increasing/decreasing the number)

Also need to be able to draw some simple line graphs. A 4.3" screen would be best, but I could opt for 3.5" if that was significantly cheaper and more availability/choices. Something like the 4.3" display by Rayman but new and will still be in production for the next few years would be perfect i think.

I am looking (and waiting for some answer) at Rayman 3.5" new display as well and it could be an option. But, if I have to go with the CrystalFontz display, since you already have the experience, and you were the first to answer my original post and with very helpful advices, I would consider paying from my limited budget for your help in any capacity to get things up and going quickly. Of course it is very nice to get free help from you and all the nice people who have responded, but I feel I should pay what I can and be fair beyond the initial free pointer advices.

By the way, how are you going with your screen display, coding wise?

Regards,
Thean.

MagIO2 wrote: »

@thean: Welcome back to this thread ;o)

well ... I think you gave us to little information about your project for providing good tips.

Do you want graphics or text-only output? How many colors would you like to have? What other tasks are there for the propeller and how much RAM do you need for that? How many I/Os do you need for the other hardware you need to add? What size should the display have?

thean

Hi Rayman,

Yes, i just read on the gadgetganster website that your PTP2 is 'almost ready'. Could you tell me a bit more about this PTP2, how much does it cost including the display, and how many colors supported? As it is not on your website yet, if i decide to get a unit now, how should I go about it? Do you have a plan for doing similar for a 4.3" display, and if so what would the price be roughly?

Regards,
Thean

Rayman wrote: »

thean, Unfortunately, although the connectors are identical, the pinout is completely different. Also, the 3.5" unit has two different modes (sync and DE).
I've now started selling a new breakout board for the 3.5" screen called "PTP2". I've posted about it recently, but it's not on my website yet...

It should be a lot better for breadboard setups because all the pins you need to wire up are all in one row...

Rayman

The price will be $40 for board and screen. Shipping is $5 extra. Just email me with any order...

This new version improves the bits-per-pixel from 6 to 8, so there are 256 unique colors...
I'll try to get a web page set up for it today...

MagIO2

As far as I understand Rays displays these are completely driven by the propeller as they don't have internal RAM. So, if you want to do graphics you will need a good amount of HUB RAM for that. The good thing with this kind of displays is the amount of PINs used (of course the 6 bit-per-pixel version). If you need more PINs for other devices, it would maybe make sense to use a NTSC display module which even need fewer PINs?!

When I started with that kind of displays (those with internal display RAM and a uC interface), 3,5" was the biggest you could get. I don't know if there are bigger devices available right now.

The state of the driver I have is pretty usefull. A few months ago I shifted the text-function from SPIN into the PASM driver, so text is now fast as well, but it's the big propeller build in font. Besides that it can:
* draw points/lines
* draw small icons with 16 colors from the full 256k color pallette
* load full-screen/full color images (in 256ms) or images into a rectangular area
* IPhone like scrolling

thean

IPhone like scrolling?! You are a wizard.

How many IO pins do you use to drive your screen? I do need as many pins as I can save. Already have to extend the IO pins (output) with two 74hc595 IC, and it looks like i will need to add a third. Ray's display will use 16 pins but i think i read somewhere that the DE mode will give me two pins back. It is a nice option to have strong graphic capability with the build in RAM on the display, but i think i will try to drive everything from the propeller, maybe store some small icons in the EEPROM, just to spice up the screen a bit? By the way, would it be an option to drive (some of) the display pins using the 74hc595 output, or would it degrade performance too much? The main thing is the screen must not flicker.

Regarding text and the propeller big font - would that be the same problem with Ray's display driver?

MagIO2 wrote: »

As far as I understand Rays displays these are completely driven by the propeller as they don't have internal RAM. So, if you want to do graphics you will need a good amount of HUB RAM for that. The good thing with this kind of displays is the amount of PINs used (of course the 6 bit-per-pixel version). If you need more PINs for other devices, it would maybe make sense to use a NTSC display module which even need fewer PINs?!

When I started with that kind of displays (those with internal display RAM and a uC interface), 3,5" was the biggest you could get. I don't know if there are bigger devices available right now.

The state of the driver I have is pretty usefull. A few months ago I shifted the text-function from SPIN into the PASM driver, so text is now fast as well, but it's the big propeller build in font. Besides that it can:
* draw points/lines
* draw small icons with 16 colors from the full 256k color pallette
* load full-screen/full color images (in 256ms) or images into a rectangular area
* IPhone like scrolling

MagIO2

I'm not really a wizard! It's only scrolling up and down and it's supported by the hardware!

Well ... the big point is, that with such a display you don't need to have display RAM on the propeller. So it saves a lot of HUB-RAM for other things. The propeller simply sends the pixels to the display ONCE and it takes care of the refresh - which means it definitely will not flicker! Fire and forget ...
Then only updates are send.


The pins you need are 8 for data and 5 for control (Only for the display, excluding the touch sensor). This sounds anoying on the first glance, BUT ...
1. If you never want to read back from the display you can save the RD-pin
2. If you never need to reset the display from the propeller, you can save another pin
3. As I said you don't have to send the image periodically like in Rays display. So the 8 data pins plus the WR-pin can be used differently during the time you do not update the screen. Depending on the data you want to display this might be a good amount of time.
This reminds me that the driver I wrote allows to free the pins, so that they actually can be reused.
4. Yes ... the CS (chip select) could also be driven by the port extender

thean

Not a wizard? You know how to drive the hardware, that's good enough for me, :-)
I like your point 3. having the 8 data pins available for other uses when not updating the screen. That's a significant advantage for me as i am scrambling for all the pins i can get even after extending with two 74hc595 ICs. And with the option of using an extra 74hc595 for the 8 LCD data pins since performance won't be an issue with the screen data refresh. Will not need to read back from the screen, but will need touch sensor, so in total will only need 9 dedicated pins.

It is however a little more expensive to Ray's solution, but opens up more possibilities and alleviates a few potential concerns.

Next is, how do you connect the CrystalFontz display to the breadboard for prototyping? Which connector do you use, etc? can you send/post a dummy guide? Hope it does not require skills beyond that of a very novice - i have seen some display with tiny connectors, all the pins so narrow and close together, and don't know how i could deal with those.

Thanks,
Thean

MagIO2 wrote: »

I'm not really a wizard! It's only scrolling up and down and it's supported by the hardware!

Well ... the big point is, that with such a display you don't need to have display RAM on the propeller. So it saves a lot of HUB-RAM for other things. The propeller simply sends the pixels to the display ONCE and it takes care of the refresh - which means it definitely will not flicker! Fire and forget ...
Then only updates are send.


The pins you need are 8 for data and 5 for control (Only for the display, excluding the touch sensor). This sounds anoying on the first glance, BUT ...
1. If you never want to read back from the display you can save the RD-pin
2. If you never need to reset the display from the propeller, you can save another pin
3. As I said you don't have to send the image periodically like in Rays display. So the 8 data pins plus the WR-pin can be used differently during the time you do not update the screen. Depending on the data you want to display this might be a good amount of time.
This reminds me that the driver I wrote allows to free the pins, so that they actually can be reused.
4. Yes ... the CS (chip select) could also be driven by the port extender

MagIO2

About point 3 ... guess you did not understand what I meant correctly. You'd only connect the CS (chip select) of the display with your shift register. All other pins should be connected directly (8 data & WR & CLK). The point is, that all those pins can be connected to other devices as well because the display will only take care if CS tells it to do so.
Of course those other devices also need to be capable of ignoring signals when they are not selected.

Oh ... and as far as I remember it makes sense to use pins 0-7 for the data-bus, as the driver is optimized.

Connecting the data pins via shift register would slow down the display updates to much!

In post #5 I gave you a link to another thread. In post #6 of that thread you can see the connector of the display. The german distributor also offers a brakeout-board and delivers the display soldered to the board. The board has pins on it which can be attached to a floppy drive style flat cable connector. So, with a old floppy drive flat cable you can easily connect it with your breadboard.

Do you already have a SD card in your setup?

thean

Hi MagIO2,

I do not currently have an SD card in the setup, but that could be an option to be added later, so some info about making the system flexible and ready for that option would be very helpful.
I found the following carrier board: http://www.crystalfontz.com/product/CFAF320240F-035T-TS-CB
Called tech support and they said it could be mounted directly on a breadboard. Would your code work with this setup?

Regards,
Thean

MagIO2 wrote: »

About point 3 ... guess you did not understand what I meant correctly. You'd only connect the CS (chip select) of the display with your shift register. All other pins should be connected directly (8 data & WR & CLK). The point is, that all those pins can be connected to other devices as well because the display will only take care if CS tells it to do so.
Of course those other devices also need to be capable of ignoring signals when they are not selected.

Oh ... and as far as I remember it makes sense to use pins 0-7 for the data-bus, as the driver is optimized.

Connecting the data pins via shift register would slow down the display updates to much!

In post #5 I gave you a link to another thread. In post #6 of that thread you can see the connector of the display. The german distributor also offers a brakeout-board and delivers the display soldered to the board. The board has pins on it which can be attached to a floppy drive style flat cable connector. So, with a old floppy drive flat cable you can easily connect it with your breadboard.

Do you already have a SD card in your setup?

MagIO2

No, not out of the box. That display-board uses a different display with a different controller. But I think that after changing the initialization it should run without further big changes because they both use a so called 8080 bus mode for transferring the pixel-data.

But I like that display and it was next on my to-buy-list ;o) The nice thing is, that it also supports 18 bit bus which would be 3 times faster than the device I have. And it has some other nice features as far as I remember.

thean

That's great - i will give it a go then.

It has SPI interface, which if I understand correctly, will save some pins. Does your code make use of that?

And, hope you don't mind me suggesting this, how about I buy you the display (with the carrier board) so you can do some work on it and i get to use the code you develop? If you cannot buy it over there I can purchase two units here and send you one. If you can also get the same thing there then let me know the cost and I will wire you the amount?

MagIO2 wrote: »

No, not out of the box. That display-board uses a different display with a different controller. But I think that after changing the initialization it should run without further big changes because they both use a so called 8080 bus mode for transferring the pixel-data.

But I like that display and it was next on my to-buy-list ;o) The nice thing is, that it also supports 18 bit bus which would be 3 times faster than the device I have. And it has some other nice features as far as I remember.