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Where do I start? — Parallax Forums

Where do I start?

GorfGorf Posts: 2
in General Discussion
Hello everyone.

I am a noob to the propeller chip world. I have two inquiries.

1st: Where is the best place on these forums or else where to learn how to generate video?

I am looking to design an updated version of an old video game system known as the Astrocade. I am looking to at first generate
the native 2 bit per pixel video from a ram buffer. So each byte will hold four such pixels. The colors are from a palette of 256 using
color registers to determine which of the 256 colors will be used. The video modes will be 160 x 102, 160 x 204 and 320 x 204.
I eventually hope to add more modes of operation to these as well. I have read and heard that these chips are perfectly suited to
this sort of project. I eventually wish to generate a 4 bit and then a 8 bit color mode using similar techniques of direct ram buffer
based video.

2nd:
If there are other propeller chips that allow for more than 32 I/O lines, I'd love to know about them or a way to get more via
cascading multiple chips if this is possible. I will need 38 such GPIO lines to emulate a 40 pin chip and it's signals.

Any help or links or points in the right direction will be most gratefully appreciated! :)

Thanks all in advance!

Steve!

Comments

  • Mike GreenMike Green Posts: 23,101
    #2: There are no other Propeller chips with more than 32 I/O lines. A lot depends on what your 38 GPIO lines are for. If some of the signals don't change quickly, you can use I/O expander chips like the 74HC595 for output lines or the 74HC165 for input lines. These can be cascaded for multiples of 8 bits, require a clock, data, and load I/O pin for each cascaded group. There are other I/O expansion chips with bidirectional I/O pins, but they're more expensive and slower.

    #1: Look at the TV I/O driver from the Object Exchange. Also, make sure you have a copy of the Propeller Manual. See if you can find a copy of "Game Programming for the Propeller Powered Hydra" by Andre LaMothe. It's probably the best description of video generation with the Propeller.
  • GorfGorf Posts: 2
    Thanks for the reply Mike.

    I figured that I may need some sort of ttl chip to expand the capabilities
    but I thought I ask anyway. I will take a look for that vid gen article as
    well. I appreciate the help.

    Again Thanks!

    Steve.
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