BATC Forum

Hi All,

In between working on DATV-Express I am working on an FPGA mini project to
make an adapter that will allow devices that use DVB-ASI (Professional MPEG encoders etc)
to work with a PC via USB. This should allow the use of surplus broadcast gear to
be used with the likes of Digilite or DATV-Express.

As I have to have some interface PCBs made I am trying to get some idea of how
many boards I should order. So I need to get some idea of how much interest there
will be in such an adapter. At the moment I am thinking of having 12 boards made.

The boards are used in conjunction with an FTDI 2322H mini module and the FPGA
board I mentioned in the first part of the FPGA article I wrote for CQ-TV.

- Charles G4GUO

Hi Charles,

Well done, this sounds V-interesting.

Sounds like you will be using the DE0-nano. Are you heading in the direction per posting "DVB-ASI for DATV" a few months ago, or do you have another cunning-plan ?

More details appreciated.

Regards,

Mark

Hello Mark,

I am using one of the cheap Chinese Cyclone II boards you can buy on eBay although there is no
reason why it couldn't be done with a Nano.

I have made a small PCB that allows me to connect the Cyclone II board up to a FT2232H mini module
board for the USB2 interface. The PCB has a DVB-ASI to 3v3 logic converter based on a 3v3
MMIC from NXP.

So far I have been able to detect the 10 bit flag sequences coming from the MPEG2 encoder so it
looks like the receive logic has a chance of working. The transmit side is a bit more problematic
as the 3v3 logic won't switch at 270 MHz on transmit. However the datasheet indicates that if I
use 2v5 logic it should work.

Altera will sell you a Mega function that does DVB-ASI and their Mega function supports the Cyclone II
device. They also include a description of how their Mega function works which is quite helpful. I had
already come up with a similar scheme myself but it is nice to know what I was proposing stands a
chance of working.

There is still a fair amount of work to do, I have yet too write the Linux/Windows code to talk to the
FT2232H module in FT245 Asynchronous mode. When it will be finished I am not sure, if I have it
working in time for the 3rd part of my series on FPGAs in CQ-TV I may include it in that as the
ATV related part of the series.

If you have any further questions be sure to ask.

- Charles