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Arduino Video Display Shield

An Arduino video display shield with integrated framebuffer and analog video output.

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This Arduino shield will make an end to your 1st project being an LED to be flashed. Now you are able to connect a display (which we are all hooked to anyways) and generate a virtual LED that is going to blink in every color you have ever dreamed of.
Now seriously, the Arduino family of compatible boards is lacking a solid hardware support option to display images, animations or video. This board provides an analog composite video display with integrated frame buffer memory accessible through SPI or parallel bus. It will not display 4K video but somebody will hack it to run Doom, Joust or Ultra-Cricket. PAL, NTSC and VGA output formats are supported, resolution is up to 640x480 with reduced color count.
Design data will be published once I have a working prototype, I believe open source can only win if a certain level of quality is present. There are too many projects of unknown state dumped into repositories all over the place.

The heart of this design is the VLSI VS23S010D-L chip. It is a 1 Megabit SPI SRAM with Serial and Parallel Interfaces and Integrated Video Display Controller, which outputs a composite video signal.

Possible video resolutions, PAL and NTSC modes might be exclusive depending on the mouted crystal (4.433618MHz or 3.579545MHz):

The chip has a 3.3V interface, so a level shifter logic is required, which is done by a MC74LVX50 buffer, which is able to handle SPI Mbps speed better that a simple FET based level shifter. A 512Kbit EEPROM for bitmaps and character memory is added, but is probably too slow for effective operation. On a suggestion of [kbdhog] the next version will have a SPI flash chip for speed and memory size. Now I am dreaming of SPI DMA, which just gave me an idea of a small PLD and a parallel flash memory to implement that.

A video opamp is available for improved signal strength when a longer cable is used, but might be bridged for testing purpose.

The circuit on the bottom left of the schematic is used to fill the 10cm x 10cm PCB space and left to the reader to figure out its functionality. ;-) I will end up with ~780 copies of this circuit which will last a lifetime or they might show up on Tindie.

Rev2 of the board (with added SPI FLASH) is being designed, might be the final one if things go well. Writing SW is so hard in comparison.

  • 1 × VLSI VS23S010D-L 1 Mbit SPI/8-Bit Parallel Bus SRAM with Video Display Controller
  • 1 × Winbond W25X20CLSNIG SPI FLASH Memory
  • 1 × Bourns CG0603MLA-5.5ME TVS Protection Diode
  • 4 × RES, 10K0, 1%, 0.1W, 0603 Resisstor
  • 1 × RES, 1MEG, 1%, 0.125W, 0603 Resistor

View all 14 components

  • Some progress

    MagicWolfi10/01/2017 at 23:20 0 comments

    I am playing with the hardware to determine the perfect setup for rev 2 of the board. Using this circuit as output driver works best and gives the nicest range from dark to bright color.


    And this is the result:


    So it will be probably 2x 22R with a protection device between on the next board. The output video opamp is still not working, difficult to debug with my scope still in the box.

  • VLSI tech support rocks x2

    MagicWolfi08/11/2017 at 02:15 0 comments

    The folks at VLSI tech support are great. [Panu] and [Kalle] are a big help with HW and SW. They even sent a full Arduino sketch to configure the VS23S010. It does configure the chip corretlyf̶o̶r̶ M̶C̶G̶A̶ 3̶2̶0̶x̶2̶0̶0̶ w̶h̶i̶c̶h̶ u̶n̶f̶o̶r̶t̶u̶n̶a̶t̶e̶l̶y̶ m̶y̶ T̶V̶ s̶e̶t̶ d̶o̶e̶s̶ n̶o̶t̶ f̶u̶l̶l̶y̶ ̶u̶n̶d̶e̶r̶s̶t̶a̶n̶d̶.̶ B̶u̶t̶ i̶t̶ i̶s̶ c̶l̶e̶a̶r̶l̶y̶ v̶i̶s̶i̶b̶l̶e̶ t̶h̶a̶t̶ t̶h̶e̶ v̶i̶d̶e̶o̶ o̶u̶t̶p̶u̶t̶ w̶o̶r̶k̶s̶.̶ N̶o̶w̶ ̶i̶t̶ i̶s̶ j̶u̶s̶t̶ a̶ m̶a̶t̶t̶e̶r̶ o̶f̶ t̶h̶e̶ r̶i̶g̶h̶t̶ c̶o̶n̶f̶i̶g̶u̶r̶a̶t̶i̶o̶n̶ o̶r̶ t̶h̶e̶ r̶i̶g̶h̶t̶ v̶i̶d̶e̶o̶ ̶m̶o̶n̶i̶t̶o̶r̶.

    With the help of VLSI tech support I had my facepalm moment for the week. Just from this picture they could tell me, that I had the crystal for PAL video mounted and not for NTSC (displeasure for some many different standards for everything). Fixing that and getting the video out termination right got me this result. YAY. Now it's only 1s and 0s and a lot of typing to program a graphics engine.

  • 1st response

    MagicWolfi07/26/2017 at 00:43 0 comments

    After some typing, compiling and syntax error fixing, this was the 1st response of the video chip on the shield:

    Initially I was scratching my head about what was going on, because page 24 of the datasheet says, the default value for the ID register is ABh, but page 49 tells the correct value of 2Bh and everything is hunky-dory.

    Now comes the easy part of figuring out how to configure the video display controller. The first image will be amazing as my only device with video input is a 40" TV.

  • 2 Prototypes

    MagicWolfi07/23/2017 at 02:18 0 comments

    2 boards are populated with all components (except the Arduino headers on one of them). One is build up with PAL crystal, the other with a NTSC version. Also only the PAL version has the additional video driver installed, it is just bridged on the other board. Initial test showed the 3.3V power rail OK and no smoke got released.

    Things to note:

    • The KiCAD Arduino shield footprint has connector through holes that are very small for regular pin headers. I almost got a press-fit connection. The extra long female headers have thinner pins and are OK.
    • All other footprints that I grabbed from the KiCAD libraries turned out to be correct (maybe I was just lucky ;)
    • Testpoints are very helpful.
    • I like silkscreen that is large enough to read without microscope.

    Now the programming begins, SPI communication first and then configuration of the video output. Then the fun starts with image display functions and porting Doom. 

  • PCBs are in

    MagicWolfi05/28/2017 at 01:50 0 comments

    Finally the bare PCBs arrived from DirtyPCBs today. This time it took the full 8 weeks, which is OK. That is what they say with the slow shipping order. The quality is very good as usual. They even managed to put a solder dam between the pads of the 0.5mm QFP footprint. This will make hand soldering super simple. And they do panels if you put multiple designs on the board by yourself. They do nice thin slots and next time I will try mousebites for even easier separation. Now I am off to the soldering iron.

    The little board is an in-line current source (* 78), which will be documented in its own Hackaday.io project.

  • Todo list

    MagicWolfi05/07/2017 at 16:51 0 comments

    As the project page does not have a Todo list feature, I will try to "re-use" a project log for this. Starting now and editing later:

    - Add 3D models for missing components in KiCAD design (RCA conn, SOT23-6 opamp,HC49 crystal)

    Rev 02:

    - DONE Add SPI flash (2Mbit, SO-8, 25x20 type)

    - DISMISSED Add some LEDs (power rails, monitor detect, SPI activity)

    - A̶d̶d̶ ̶b̶u̶t̶t̶o̶n̶ ̶o̶r̶ ̶j̶u̶m̶p̶e̶r̶ ̶t̶o̶ ̶e̶n̶a̶b̶l̶e̶ ̶t̶e̶s̶t̶ ̶m̶o̶d̶e̶  testpin is for factory test only :(  

    - DONE Add pull-up resistors on signals nWP_5V, nHOLD_5V

    - DONE Disconnect signal Testmode(_5V), it is for factory testing only

    - DONE Add in-line resistors on signals nWP_5V, nHOLD_5V on the 'left side' of the pull-up/downs.

    - DONE Use 22R - TVS - 22R instead of 75R output impedance matching resistor. TVS type: CG0603MLA-5.5ME

    - DONE with  74LVC4245A Replace 74LVX50 with TXS0102 /  TXB0106 / 74LVC4245A / SN74LVC1T45 for availability.

    -  Add monitor detect line.

  • Virtual debuging

    MagicWolfi04/17/2017 at 02:12 0 comments

    If you look at things long enough, mistakes get noticed. I just updated the schematic with a 512Mbit EEPROM (not a bug) and replaced the 74LVC07 driver with a 74LVX50. The LVC07 would have the 5V tolerant inputs for the signal from Arduino to the video chip which I was looking for, but is an open-drain driver which does not really help with SPI signals. So I replaced it with the 74LVX50 which has the same package and pinout. Easy fix when the parts are not ordered yet.

View all 7 project logs

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Discussions

Tim Trzepacz wrote 10/31/2017 at 10:58 point

So, this looks very interesting, but I'm wondering if there is going to be anything in the hardware to speed up building your drawings. Sending bitmaps pixel-by-pixel over SPI is the way we do it with LCD screens now, and is very slow when you are trying to update the whole screen. It looks like you at least have paletted bitmaps with lower bits-per-pixel than those LCD screens, so that might speed stuff up a bit, but it would be nice if the hardware had something like the sprites and character mapped scroll planes of the old video game systems. Some sort of "blitter" style system might also work, although I get the impression performance wouldn't be as good.
I'm sure you've already got your plan and specs set tho, so it's silly for me to suggest anything.
I look forward to seeing the final result.

  Are you sure? yes | no

MagicWolfi wrote 10/31/2017 at 15:38 point

Hello Tim. Thanks for the interest in my project. The controller has hardware support for a simple memory block move operation, which is configured in 3 register write commands. For the interface speed, the VLSI folks managed to display a full video stream through their audio SoC (used as data host) handling all data traffic.

http://www.vsdsp-forum.com/phpbb/viewtopic.php?f=15&t=2176

Of course this will not happen with an Arduino as the host. For a full graphics engine as you are suggesting, a FPGA or dedicated uC would need to interface to the parallel memory bus for maximum speed and handle all the higher level functions. I would love to do that, but then I would use a different display solution and go DVI or HDMI. Cheers.

  Are you sure? yes | no

chibill wrote 10/30/2017 at 20:13 point

This is cool! Might make my recent project using basically an Arduino Due easier. (Less low on the main chip)

  Are you sure? yes | no

MagicWolfi wrote 10/31/2017 at 01:38 point

Currently the IO voltage is 5V so it would not work together with a 3.3V Due. But your comment triggered an idea to use the IOREF pin to make it compatible to 3.3V boards. I will add this to the next revision. Thanks for that.

  Are you sure? yes | no

chibill wrote 10/31/2017 at 15:56 point

Mostly I was talking about applying your work as part on my full board. (Making a PCB with the SAMX3E (due's chip) with a different set of IO broken out. Like the Ethernet MAC and Can bus.) Adding this sort of chip and is supporting hardware would give it a way for displaying information on a screen. )

  Are you sure? yes | no

Nard Janssens wrote 10/24/2017 at 17:59 point

Have been searching for this a long time. Can't wait

  Are you sure? yes | no

MagicWolfi wrote 10/31/2017 at 15:39 point

Stay tuned. Boards will be available on Tindie soon.

  Are you sure? yes | no

Nard Janssens wrote 10/31/2017 at 17:43 point

Do you have any indication of the costs of the shield? (Another possibility for me as a video display shield would be the Arduino Due with the DueVGA library by Stimmer. So I am wondering which would be cheaper.)

  Are you sure? yes | no

kbdhog wrote 10/02/2017 at 01:35 point

I can't be only one thinking "awesome progress!!!", and also can't wait to try one out!

  Are you sure? yes | no

MagicWolfi wrote 10/03/2017 at 00:48 point

Thanks. As I said in one of the logs, the SW is the hard part. I would like to release this not only as a piece of hardware, but at least want to show some basic functionality. And the list of functions is long: different resolutions, draw pixels and boxes in RGB, display images that get downloaded to the board, character generator and maybe a demo that is somewhat useful (i.g. displaying a thermometer and having a sensor hooked up to show live updates of temp changes.

  Are you sure? yes | no

Starhawk wrote 08/09/2017 at 21:40 point

That extra board looks a lot, from the schematic, like a simple constant current setup for driving LEDs...

  Are you sure? yes | no

MagicWolfi wrote 08/09/2017 at 23:57 point

Bingo! It is almost constant current, as it slightly increases with higher voltage. The nice part is, that is only has 2 connections so it can be easily wired inline into any  LED on wires, that do not need variable brightness control.

  Are you sure? yes | no

Starhawk wrote 08/10/2017 at 00:01 point

Haha, I thought that might be it. It's not an uncommon design. I saw it on Google over a year ago...

By the way, I absolutely love the idea of this Shield (the video part, not the LED driver) and that you're actually making them...

  Are you sure? yes | no

kbdhog wrote 04/11/2017 at 14:03 point

If I may offer a little idea: Since you already have SPI driving this board, perhaps add a nice sized SPI-flash chip (2mbits?). This can be used to store character fonts, icons, even entire bit-maps. Thereby removing that storage burden from the Arduino's memory space. The SPI-flash would be loaded once (via RS232 serial commands?) and then maybe you can have a write-protect jumper as well... making the contents somewhat "permanent".

  Are you sure? yes | no

MagicWolfi wrote 04/12/2017 at 21:17 point

Thanks, kdbhog. The I2C EEPROM on the board was planned to be for this purpose, I just used a small 24c 64 as placeholder, the biggest I can use is a 512Kbit. You are absolutely right, an SPI flash chip would give much larger storage and higher performance. I will add this for the next rev. Boards should arrive in 2-6 weeks, stay tuned, there will be updates. Cheers

  Are you sure? yes | no

kbdhog wrote 04/11/2017 at 02:38 point

Very often, 640x480, or NTSC/PAL, are *just enough*. Especially for diagnostic screen output, or simple control systems. I like it! I look forward to seeing this work.

  Are you sure? yes | no

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