Jump to content
Mr.RC-Cam

Maxim's MAX7456: Text based OSD Chip

Recommended Posts

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. :)

Share this post


Link to post
Share on other sites

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,

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites
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'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.

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.

post-13-1196729707_thumb.jpg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×