Video monitor

Comments

• AndreL Posts: 1,004

  2006-04-22 00:12 edited 2006-04-22 00:12

  Since software generates video on the propeller, depending on how close the driver follows the NTSC spec, the better the image. However, LCD and plasma monitors are VERY touchy as is PAL, so my first suggestion is if you are not in the USA, get a nice multisystem CRT set ($99-199), I suggest the panasonic model. If you are in the US, then I suggest·simply·a plain old CRT (new of course), no fancy LCD or plasma, make sure you have front video connectors and that's about it. Also, when playing with video drivers and doing graphics, you will find that front controls for brightness, tint, etc. are nice to have, I hate fumbling over a remote to change the tint, so if you can find a set that has front controls as well, that's good when doing video programming.
  
  Additionally, since software does generate video, you can exceed the NTSC spec for example and sets with a slightly better mask, better chroma/luma seperation will give a better image. This is moot of course for most people, since most people buy an HDTV then watch a compressed digital cable image that has 25% of the resolution as NTSC from the 50's, but think the image looks good, but being that I am a graphics programmer, I sit and look at pixels and want stuff perfect.
  
  One suggestion is to simply take your propeller prototype with a graphics demo down to your local electronics store with batteries and "see" for yourself which sets, models, manufactures looks the best with the standard parallax video driver, that's a good starting point and how I typically run tests myself when making video hardware. Another thing to watch out for is that the propeller PLLs the input frequency XTAL, so if you use a XTAL as the clock source then depending on how many digits of accuracy you have, that dictates the error in the final clock frequency which then inturn dictates the error in color burst synthesis in your timing chain, so either use an external OSC at 5.00000000 or 10.0000000000 Mhz as the source, OR write some code, so you can sweep the frequency in real time, until you get color. For example, if you get an xtal at 10.000 Mhz, that is accurate to 3 decimal places, then your error is +-1000 Hz, now scale that error by·8 due to the PLL +-8000Hz which can definitely cause a really anal set to not lock onto the color burst which is 3.58Mhz roughly for NTSC and 4.43 Mhz for PAL (most common versions).
  
  Andre'
• FORD Posts: 221

  2006-04-22 02:43 edited 2006-04-22 02:43

  Andre,
  Thanks for that, I know nothing about the stuff, but most of what you have said makes sense to me, especially the bit about using accurate crystals. I will haev a look at the CRT option, but later I will need to be able to use a small LCD panel (once I've learn't a bit more about the stuff).
  
  Thanks again,
  Chris
  Western Australia.
• cocokiwi Posts: 75

  2006-04-22 08:55 edited 2006-04-22 08:55

  FORD said...
  I know absolutely zip about video stuff.
  I would like to set up a monitor for debugging purposes, but first I need a monitor.
  
  1- What is the simplest type to set up with a propeller ?
  
  2- Is the monitor detailed below OK to use (and simple) and if it is, can somebody post a schematic for the components needed around the propeller.
  I have cut the information from a brochure of one of our suppliers.
  Thanks,
  Chris
  
  Two RCA composite video inputs and one audio input are provided for a multi source system.
  This is truly a versatile monitor, it has low power consumption, wide viewing angle, and is NTSC and PAL compatible.
  It is equipped with On Screen Display enabling the user to easily control the colour, contrast, hue, brightness, and volume. A very slim and small infra red remote control is included. It has reverse image capability adjustable by pressing a button. The mirror-image function on this unit makes it ideal for buses with a camera to view behind while reversing.
  Unit comes with an adjustable swivel bracket with double sided tape for adhesion on clean flat surfaces. A 4 pin mini din to 2 RCA and power cable is also supplied.
  
  Specification:
  - System - NTSC/PAL
  - Power Input - 12VDC
  - Power Consumption· 10W
  - Video Input· Composite Video Signal 1Vpp 75 Ohm
  - Audio Input - -10dB (10k Ohm)
  - Operating Temperature - 0 - 85 c
  - Screen Size· 7inch (diagonal width)
  - Display Method - TFT Active Matrix System
  - Resolution - 1140(h) x 234(v)
  - Weight - 800g

  ··· Hmmm,
  ··· Since the prop chip is not at this time into PAL tv this might be a way to get around it,
  
  ·· This might work very well, I was doing this for my old Color computer so·I could use it with my TV
  
  ·· via the S-VHS output as RGB monitors are hard to come by nowdays,someone on my cocosig came up with this,
  
  ·· so·I looked into it and ordered some chips to play with,I,m building one right now
  
  ·· A chip from Analog Devices AD723/4/5···· any one will work, the AD795 is the better one! But the AD 723 is simpler!
  
  ·· what do it do!
  
  ·· It converts RGB/VGA to NTSC/PAL··· S-VHS· or Composite in either NTSC/PAL
  
  ·· a small chip SOIC 16 lead wide body· simple components resistors/caps
  
  ·goto· www.Analog.com·· and get the datasheet on anyone of the above.
  
  ·cost around $30 to build one!
  runs on 5v 30 ma·and powers down to <1uA
  
  ·Dennis
• cgracey Posts: 14,133

  2006-04-22 09:12 edited 2006-04-22 09:12

  The Propeller can generate VGA, NTSC, and PAL video signals. It works nicely to use 3 pins to generate a composite signal which can go into the video RCA jack on your TV. We have an object called 'tv_terminal' which you start, and then write to like a tty terminal. It has methods for printing strings, decimal, hex, and binary. It's dirt simple to use.
  
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  Chip Gracey
  Parallax, Inc.
• cocokiwi Posts: 75

  2006-04-22 09:32 edited 2006-04-22 09:32

  Chip Gracey said...
  The Propeller can generate VGA, NTSC, and PAL video signals. It works nicely to use 3 pins to generate a composite signal which can go into the video RCA jack on your TV. We have an object called 'tv_terminal' which you start, and then write to like a tty terminal. It has methods for printing strings, decimal, hex, and binary. It's dirt simple to use.
  
  

  ·Another Night owl (grin) I love the Prop! hopefully have one to play with soon!
  ·I,m an old Color computer user,I still run the old os9/coco sig on Delphi
  
  ·Now Delphiforums,Marty Goodman the ORG manager·is a friend of mine!
  
  ·I figured that could just about emulate anything!
  ·This chip once built on a board·will plug directly into the VGA and give
  
  ·Composite and S-VHS for a TV in NTSC or PAL
  
  ·just a quick way to do it(grin) I do have a copy of that program!
  
  ·Just waiting,and waiting,and Etc,Etc! for the Prop!( )
• LoopyByteloose Posts: 12,537

  2006-04-23 03:47 edited 2006-04-23 03:47

  I am wondering if buying Andre's book will be useful for the Propeller.
  I know it was originally written for the SX chips, but it is a Tutorial - isn't it?
  
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  "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
  
  ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
• FORD Posts: 221

  2006-04-23 03:58 edited 2006-04-23 03:58

  If his book is written as clearly as his reply above, where do I get one ?
  
  Cheers,
  Chris
• Forrest Posts: 1,341

  2006-04-23 04:16 edited 2006-04-23 04:16

  You can download Chapter 11-Hardware of Andre's XGS book by going to Andre's website and clicking on the book (upper right side of the page) www.xgamestation.com/index.php
• LoopyByteloose Posts: 12,537

  2006-04-23 16:24 edited 2006-04-23 16:24

  I believe that Parallax is selling the CD version of Andre's text·for $29.95. It is something like 850 pages long.
  But, it seems like the time has come to add a copy to my collection.
  
  I went downtown today to see about buying a color CRT monitor for the Propeller. They had them a few months ago, but it seems that there are none to be had in Kaohsiung, Taiwan.· At least not new.
  
  Either I will get a TV with monitor input or it will have to be a flat screen.
  
  This all may seem strange to Americans, but Taiwan gets very nervous about holding obsolete inventory.· I am beginning to fear that DIPs will vanish suddenly too.
  
  
  So all those bargains on EBay just don't exist here.
  
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  "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
  
  ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan