Ruth Hendrix

Looking for Help with HCS08

Discussion created by Ruth Hendrix Employee on Jan 24, 2006
This message contains an entire topic ported from a separate forum. The original message and all replies are in this single message. We have seeded this new forum with selected information that we expect will be of value to you as you search for answers to your questions.
Posted: Fri Nov 11, 2005 4:22 pm    
I am trying to get this Hook a controller up to this board and get it to display what ever i select onto the TV what all do i need for this
Posted: Tue Nov 15, 2005 1:51 pm  
Well, I'm sure a few of us would love to help, but you don't even give us a starting point. What is it you would like to do?

Do you want to use an '08 processor to help output a video signal for display on a television?

Posted: Wed Nov 16, 2005 4:32 pm    
Well I am a computer programmer but i m new to programming processers. What I want to do is take a nintendo controler that has a data stream and press the up arrow and see an up arrow display on my TV, press the Down arrow and display a down arrow on my TV, press the A button and see an A on my TV. You get the picture.

I dont know where to Start. I am looking for someone to give me a starting point. I have the HCS08 board. I can write a program on that to display the lights but i dont know how to get it to read a data stream. If anyone has done something like this please give me some pointers.
Posted: Fri Nov 18, 2005 2:21 pm    

What you can do is re-create a video signal using an external DAC, probably parallel for speed, to create a rudimentary video signal based on an internal bitmap in the processor. Perhaps not even a DAC, see below.

Here is some info based on a PIC device, but you can easily translate this to '08 as well:

As long as you can get your synch signals correct and the timing reliable (which shouldn't be too hard), your screen resolution would then be limited to how fast you can change data between the pulses without effecting the timing.

I would look at creating the synch pulses using a timer interrupt, and use this event to trigger a free-running line of data from a memory map after the event to create the video data stream. Then your resolution can be variable based on CPU load. You would have to find out when to stop sending data before the next pulse through trial and error.

Rather than using the DAC for generating the synch, sum a digital output through a resistor with the DAC output in a high-speed video-capable opamp. That way you can use a timer output pin to create the pulses you need, and will give you more dynamic range in the video signal with the DAC. You may find that you don't even need a DAC, but a simple resistor array to the summing junction of the op-amp to give you 4 or 8 levels. Very fast and cheap that way. It will also reduce the amount of memory you will need to store the bitmap, but also reduce they grey levels you can use.

Sounds like a fun project, and quite do-able. Keep us posted!

Posted: Fri Nov 18, 2005 2:42 pm  
OK thanks for the help let me get started on that and i will let you know if i have any problem and how it worked out.

Thanks for the Help
Posted: Fri Nov 18, 2005 2:53 pm   

maybe this could e helful for you.