I've got a demo board on its way.
Maxim's MAX7456: Text based OSD Chip
Started by
Mr.RC-Cam
, Nov 28 2007 04:36 PM
4 replies to this topic
#1
Posted 28 November 2007 - 04:36 PM
I had given up all hope that the electronics industry would ever see a dedicated OSD IC again. They fell out of favor due to the their cost burden in consumer products (cheaper for the offshore mfg's to go with a custom solution). But to my surprise, earlier this month MAXIM announced their new OSD IC. Click for press release.
I've got a demo board on its way.
I've got a demo board on its way.
- Thomas
#2
Posted 29 November 2007 - 01:29 AM
hehe, I allready have the chips here !
I wanted to test them.
but the chars are really huge !
and not possible to use same number of lines on PAL/NTSC
so the chars will be much higher on NTSC, and less lines to put txt,
I wanted to test them.
but the chars are really huge !
and not possible to use same number of lines on PAL/NTSC
so the chars will be much higher on NTSC, and less lines to put txt,
Thomas Scherrer OZ2CPU www.webx.dk
#3
Posted 29 November 2007 - 02:58 AM
hehe, I allready have the chips here !
I wanted to test them.
but the chars are really huge !
and not possible to use same number of lines on PAL/NTSC
so the chars will be much higher on NTSC, and less lines to put txt,
Why am I not surprised, I'm sure you'll get it to work properly!
Cheers,
Sander.
Cute, cuddly and colorful, beware the nasty bite
#4
Posted 29 November 2007 - 03:23 AM
The 4455 is an alternative.. but $100, and 8 channels. Been trying to get them to make a single channel of it, they're not having it through.
#5
Posted 03 December 2007 - 04:55 PM
I'm not concerned about the larger character size, especially since it is similar to the retired STV5730A OSD IC, which worked nicely for me. Frankly, nothing beats the quality look of a onscreen text character that has a reverse contrast outline around it. It's great to see the MAX7456 can do that too.but the chars are really huge !
and not possible to use same number of lines on PAL/NTSC
so the chars will be much higher on NTSC, and less lines to put txt,
I was so interested in recreating the STV5730A's onscreen look that I started a custom solution of my own over the summer. I can say it is not a low parts count way to solve things. For example, anyone that has seen Decade Engineering's old BOB2 OSD (it used a STV5730A), and compared it to their new BOB4, the parts count is enormously higher on their new design. Their BOB4 does not use an OSD IC; they custom created one using a FPGA and endless number of components. What they came up with is brilliant though.
In my quest to create my next OSD product, I spent some time with the Parallax Propeller Microcontroller. This MCU has hardware video generation, but in a somewhat limited way. What's nice is that it can create outlined text. But, the Propeller lacks some of the features I wanted, so I went off and started a custom OSD board design based on a pair of DSP chips. It has programmable character brightness, outlined text, and other nice OSD features. It is bit expensive due to the required components. Although size would would shrink a lot with a SMD conversion, expected costs were higher than I wanted to see. A partially stuffed proto board is shown below.
I have my MAX7456 samples now. So, all that summertime effort is on a one way trip to the archives. I don't mind the lost progress, it's all a part of the design process. Interesting enough, the first product that was going to use my custom OSD was a video overlay board for the EagleTree telemetry system. But they recently announced they would sell a OSD add-on for their system. So, I'm moving on to another game plan. Again, no big deal, its just the way things go in this business.
Long story short, I'm excited by MAXIM's new part! And from my long-winded story, you can see why.
A partially stuffed OSD prototype board is shown below. This design is headed to the trash can. Half the parts will be displaced by the new MAX OSD IC. A final design would use SMD construction, so it will be much smaller due to less parts that are also smaller in size.
- Thomas



