question about RCA to Breadboard

Kris Cardoen · 2012-09-08 01:49

I have bought a RCA to Breadboard Adapter and Mini LCD A/V Color Display for my propeller board

I have connected the board via a 1k resistor.

Then I have tested the code below

CON
  _clkmode = xtal1 + pll16x                      ' System clock settings
  _xinfreq = 5_000_000
  BASE_PIN = 5                                  ' DAC base pin is P12
                                               
OBJ
  tv      : "tv_terminal"                        ' Declare tv_terminal object
 
PUB start | i
  tv.start(BASE_PIN)                             ' DAC base pin is P15
  tv.str(string("This is a test message..."))    ' Display message

This works fine :-), but what I don't understand is how

it uses the object
("tv : "tv_terminal" ' Declare tv_terminal object ") => I don't have tv_terminal.spin on my pC ????

what object do I need to download to develop more code, for now I can only show the one line
Any help would be much appreciated!

Duane Degn · 2012-09-08 07:45

Kris,

The file "tv_terminal.spin" is in the "Library" folder inside the Prop Tool's folder(which is inside the "Program Files (x86)\Parallax Inc" folder.

If you want to use color with your TV look at the schematic of the Demo Board (in the "Help" section of Prop Tool) to see what resistors are used (the tv signal generator uses more than one pin).

The tv_terminal object behaves a lot like a serial object. You use "str", "out" (IIRC, this is the same as PST "char" or FDS "tx") and the other methods in object to place text on the TV screen. The main downside to using a TV as a debug screen is the amount of memory it uses. You ought to look at the "Graphics_Demo" (in the "_Demos" folder of the "Library" folder) to see about using graphics with the TV(though this uses even more memory).

Mike Green · 2012-09-08 10:03

The TV output of the Propeller normally uses 3 resistors and 3 I/O pins of the Propeller (the 1st 3 of a multiple of 4) as shown in the Demo Board schematic. There is a special 1-pin TV driver that provides Black & White text that you can find in the Propeller Object Exchange (ObEx). A 1K resistor will work, but a more complex circuit as described in the I/O driver source code will work better.

To use more than a single line, you have to use control characters like carriage return (13) and line feed (10). Look at the tv_terminal.spin source code for a description of these along with tv_terminal_demo.spin and tv_text_demo.spin in the "Library" folder.

Oldbitcollector (Jeff) · 2012-09-08 19:14

This might help you..

Jeff

Kris Cardoen · 2012-09-09 06:41

Thanks for the info!

Just one more question.
In the code I only have to specify the basepin. I guess that the program will assume that the other pin are basepin +1, basepin + 2, etc?

potatohead · 2012-09-09 13:13

Correct. Video pins are blocks of four or eight typically, depending on TV or VGA output.

question about RCA to Breadboard

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