VGA with 3 Pins ***UPDATE*** VGA with 5 Pins and 8 Fore/Background-Colors
zx81vga
Posts: 56
Hello Propeller-Friends,
sometimes i need more Pins on the Propeller with VGA.
The Result is:
VGA3PIN 1.0
here to find
http://propeller.ws-nbg.de/main.php
Greetings from Nuremberg, Germany
Werner
sometimes i need more Pins on the Propeller with VGA.
The Result is:
VGA3PIN 1.0
here to find
http://propeller.ws-nbg.de/main.php
Greetings from Nuremberg, Germany
Werner
Comments
If you want to save another pin, I have found some monitors will allow a composite sync signal to be used instead of separate H/V syncs (I have a couple of Sony Trinitrons that do this). Depending on your monitor support you can also resistively add the signals to combine sync and green video together resulting in a 2 wire VGA cable. Here is a snippet of a circuit I successfully used with the P1 when I was pin limited to get simultaneous composite and VGA signals generated. I was using a 1 pin composite object available from the OBEX if I recall correctly and my own two pin VGA using Sync on Green. So just 3 pins gave me my mono VGA and composite video leaving a lot of pins freed which I needed for my other buses [img][/img]
In another forum, the claim was that pretty much all VGA Monitors simply XOR H & V, then extract sync info.
Could pay to test that ?
there is an Update
Changes in v1.1
VGA 256x192 BMP
VGA 320x240 BMP
VGA 512x384 BMP
added.
Greetings from Nuremberg, Germany
Werner
Sync compositing in the computer industry.
As these signals are normally generated by digital logic circuits in computer systems, the composite sync signal has also commonly been produced simply by OR-ing (a)
or exclusing-OR-ing (b) the horizontal and vertical sync signals.
The former practice is commonly known as “block sync,” and no horizontal pulses occur during the composited vertical sync pulse.
The XOR compositing produces serrations similar to those produced in television practice, but without preserving the falling edge position.
Note also that, since the vertical sync in typically produced by counting horizontal sync pulses, the V. sync leading and trailing edges usually occur slightly after the H. sync leading edge; this can result in the spurious transitions shown in the composite sync output if the two are simply XORed, as in (b).
there is a new Update for VGA3PIN
Changes in v1.2
Greetings from Nuremberg, Germany
Werner
Here is a 5 PIN Version:
VGA5PIN 1.1 with 8 Fore/Background-Colors
here to find
propeller.ws-nbg.de/main.php
Have Fun...
Greetings from Nuremberg, Germany
Werner
How does it compare to the PropGFX?
Thank you
Here is a 4 PIN Version:
VGA4PIN 1.0 with 4 Fore/Background-Colors
There are also Updates for:
VGA3PIN 1.3 Textmode 320x240 Font 8x8, 8x12, 8x16 added.
VGA5PIN 1.2 320x240 Font 8x12 and 320x240 Font 8x16 added.
As allways here
Have Fun...
Greetings from Nuremberg, Germany
Werner
It was based on the pin being tristate when no HS or VS, 0 for HS and 1 for VS. The output had a series 5K followed by 10K to Vcc and a series 5K followed by 10K to ground.
The gate inputs come from each 5K-10K joint.
Trying to recall the XOR connections
Found it! Not quite the same, but you can get the idea
@Cluso99
Thanks for the Info...
But i must work on the ZXGame Interface by @Bean
Werner
Now that the P2 is here, have you thought about porting the project to it instead.
Werner,
Thanks for sharing these Prop VGA utility programs.
I browsed your site but I could not find any schematics for connecting the Prop pins to the VGA pins.
Please can you point me to schematics or descriptions for the hookup.
Thanks in advance . .
The Schematics are in the ZIP-Download, Folder "EAGLE".
Werner