VS23S010C-L Hardware App Notes?

[TonyD_]

Hi

The VS23S010C-L looks a really interesting chip but I can't seem to find any h/w apps notes to get me started?

So I have few questions:

As it's a 3.3V device, are the I/O signals 5V tolerant?

Which of the Video0 to 3 signals are YUV?

Do you have any recommendations/suggestion for the video output circuit (op-amp or transistor) ?

thanks

Tony

[pasi]

Hi,

The pins are not 5V tolerant. The maximum voltage of 3.6V should not be exceeded.

Chapter 5.1 of the VS23S010 datasheet shows 75Ohm resistor and capacitor on VideoOUT#0 as the suggested composite video output circuit.

http://www.vlsi.fi/fileadmin/datasheets/vs23s010.pdf

There is only one DAC, so YUV are not available separately.

[Panu]

Do you have any recommendations/suggestion for the video output circuit (op-amp or transistor) ?

The video out is a current output, e.g. if you short circuit it to ground, it will produce a certain amount of milliamperes for white level, certain amount of milliamperes for black level and zero current output for sync level. It produces the proper video voltage levels into the 75 ohm load inside the TV. So it doesn't really need any external circuits, except for protection, perhaps. We've included the VS23S010 TV-Out into the VS1010 Developer Board; let me see if I can get that schematic published real soon

Which of the Video0 to 3 signals are YUV?

Only a single output variant has been produced (so far) so the only video out is Video0 and it is a composite video output. PAL with a PAL crystal or NTSC with an NTSC crystal. YUV operation is internal to the IC.

-Panu



8 bit palette test on a VS23S010C-L, March 2016 by Panu

[Panu]

Here's a schematic snippet of the VS1010 developer board (may be old version) that shows the VS23S010 and the video out connection.

vs1010-vs23s010.png (55.92 KiB) Viewed 7418 times

The 22R + TVS + 22R is ok, keeping the VS23S010 DAC driver out of its saturation region better than having a 75R in series, and provides some protection against transients. It's ok at least for a local connection to a television set.

Here's a picture of the VS1010 developer board. VS23S010 is the LQFP-48 package. From there the video signal goes to the RCA connector.

vs1010dev_small.jpg (311.88 KiB) Viewed 7419 times

Link: VS1010 Developer Board: http://www.vlsi.fi/en/support/evaluatio ... board.html

-Panu

[TonyD_]

Thanks Panu & Pasi for the additional information and especially the schematic.

I'm planning on doing a small breakout board for the chip to use with embedded platforms such as Ardunio and others. The STM32 is my intended target uC.


Tony

[Panu]

That's a great idea!

Here's a couple of suggestions to you:

- Include the quad IO SPI bus (4 bit SPI) to the MCU, that's the most efficient bus for drawing video. The 8 bit bus is fastest overall, but it can only address 32 bit boundaries. That's useful for full screen video but cannot be used for addressing individual bytes (pixels).

- Bring out the BLOCKMOVE0 pin to an IO pin on the MCU. That's an output from the blitter that signals that a block move has been completed. With this signal you can start the next block move immediately after one block is moved (use it as interrupt request or poll it). Note also that the blitter registers are duplicated, e.g. after starting one block move, the next one can be prepared while the first is in progress. Block moves are the most efficient operation for scrolling, tile graphics and text output.

- IO4, IO5, IO6, IO7 can be used, for example, for generating sync signals. One useful use is to program one of these pins to emit a pulse for the first line of the video frame. This can be used for making a video frame interrupt on the MCU. Another signal could emit a pulse at the start of every line. I've also used those signals to make VGA sync pulses.


-Panu