I've been playing around with an odd experiment from the '80s called Visicode.
A method for transmitting BASIC code via a flashing square on a TV screen during a broadcast of the
British computer show "Four Computer Buffs". Video: https://www.youtube.com/watch?v=xxo1Gs46ti0
Magazine article with circuit diagram: https://archive.org/details/PersonalCom ... 4/mode/1up
I've built the circuit (C64 version) and copied the programs. The system assumes all PAL equipment, but as I only have NTSC,
I wonder if there's a way to modify this code so it runs at PAL speed on an NTSC machine, or to change the sample rates on the PB7 (L) pin of the userport?
Receiver program:
Code: Select all
10 rem receiver program for commodore 64
20 a=49152
30 read n:if n<0 then 60
40 poke a,n:a=a+1
50 goto 30
60 end
70 data 165,43,133,252,165,44,133,253,169,0
80 data 141,3,221,32,228,255,201,0,240,249
90 data 32,77,192,32,117,192,133,254,32,77
100 data 192,32,117,192,201,0,208,4,165,254
110 data 240,25,32,77,192,32,117,192,32,77
120 data 192,32,117,192,32,77,192,32,117,192
130 data 201,0,208,246,76,20,192,96,160,124
140 data 136,208,253,202,208,248,96,169,9,133
150 data 251,173,1,221,41,128,208,249,162,15
160 data 32,68,192,169,0,72,173,1,221,10
170 data 104,106,162,30,32,68,192,198,251,208
180 data 240,162,30,32,68,192,96,-1