Graphics_Demo basepin selection

Comments

• Peter Jakacki Posts: 10,193

  2018-03-13 04:31

  K2 wrote: »

  In TV_Text_Demo it is relatively easy to see that the output pin group is selected by passing the value 12 to TV_Text at start up. I've made use of that code for many years to drive composite monitors of various sorts. Now I need composite video graphics.
  
  In the Graphics_Demo -> Graphics -> TV combo, the specification of the output pin group seems to be somewhat obfuscated, especially for a Demo program. Is there something obvious I'm overlooking?

  
  Sorry, why wouldn't you just post the code in question or link directly to it?
  I'm sure if I try and guess I might get it right but I couldn't be bothered.
  
• Ariba Posts: 2,682

  2018-03-13 05:40

  You find the description of the pin settings in the TV.spin object:

  ''  tv_pins
  ''
  ''    bits 6..4 select pin group:
  ''      %000: pins 7..0
  ''      %001: pins 15..8
  ''      %010: pins 23..16
  ''      %011: pins 31..24
  ''      %100: pins 39..32
  ''      %101: pins 47..40
  ''      %110: pins 55..48
  ''      %111: pins 63..56
  ''
  ''    bits 3..0 select pin group mode:
  ''      %0000: %0000_0111    -                    baseband
  ''      %0001: %0000_0111    -                    broadcast
  ''      %0010: %0000_1111    -                    baseband + chroma
  ''      %0011: %0000_1111    -                    broadcast + aural
  ''      %0100: %0111_0000    broadcast            -
  ''      %0101: %0111_0000    baseband             -
  ''      %0110: %1111_0000    broadcast + aural    -
  ''      %0111: %1111_0000    baseband + chroma    -
  ''      %1000: %0111_0111    broadcast            baseband
  ''      %1001: %0111_0111    baseband             broadcast
  ''      %1010: %0111_1111    broadcast            baseband + chroma
  ''      %1011: %0111_1111    baseband             broadcast + aural
  ''      %1100: %1111_0111    broadcast + aural    baseband
  ''      %1101: %1111_0111    baseband + chroma    broadcast
  ''      %1110: %1111_1111    broadcast + aural    baseband + chroma
  ''      %1111: %1111_1111    baseband + chroma    broadcast + aural
  ''      -----------------------------------------------------------
  ''            active pins    top nibble           bottom nibble
  

  and yes, it's a bit complicated.
  Simplified:
  Set the pin group in the upper nibble and the lower nibble to %0000 if you use the lower 4 pins of the pingroup, or %0101 if you use the upper 4 pins of the group.
  
  A possible calculation from the pin number (untested):

    tvparams[2] := pin>>3 << 4 | (pin>>2 & 1) * %0101
  

  
  Andy
  
  
• K2 Posts: 691

  2018-03-13 14:18 edited 2018-03-17 20:50

  Thanks Andy! In searching for something familiar I glazed right over that. Repeatedly.
  
• K2 Posts: 691

  2018-03-17 21:02

  In more than 10 years of using the Propeller, I've assiduously avoided graphics (and robots, ugh!). Well, a need for graphics on a little automotive display finally materialized. It was just a matter of time, I suppose.
  
  Anyway, I'm stunned and amazed at what Chip created in Graphics.spin. Today's amazement centers on his creation of a vector font based on simple drawing primitives and a specifiable pixel.
  
  This worries me. What if robots are actually clever, useful, or fun?!
  
  
• potatohead Posts: 10,253

  2018-03-17 21:55

  Yes, that TV driver and graphics library can do a whole lot more than it appears at first glance.