7900 player is not working so had to use bd 8350 player to check signals with oscilloscope when playing normal vhd movie disk.
Pin 1 is ground for all signals.
Pin 2 has analog signal, (mono audio?), but that was showing waveform even in pause mode(much white noise due to old capacitors?).
Pin 3 has almous 5ms long ttl datastream, so it is connected in 8350 but not on 7900.
Pin 4 has composite video on 2V offset level? There is clearly that h sync interval seen.
Pin 5 has constant 5v signal( this was not ground pin, but goes to some transistor collector pin.)
Pin 6 has composite video on 0V offset level? There is clearly that h sync interval seen.
Pin 7 has ttl level H-sync(or also v sync?)
Pin 8 has some ttl level signal
Pin 9 has ttl level H sync(or also v sync?)
Pin 10 has some ttl level signal
Pin 11 is constant 5v level
Pin 12 has some ttl level signal
Pin 13 has roughly 66.7ms pulses(so 4 times ntsc v sync period). that was the pin that i thought was not connected, but is coming from 8050H pin13(DB1) via hex inverter.
The basic commands _super0, _super1, _super2, _super3, and _super4 are actually in victor hc95 normal basic, as i can execute those without the c9d card and same effects appear. Or this card is extending the functionality of these existing commands or why are those listed in rom?
Only _vp command comes from c9d card rom.
How are these superimpose commands suppose to work? I connected vhd to video input of hc95, and hc95 is connected to tv with composite output. I can see only the vhd picture when giving _super4( no computer screen). With _super1 i do not see or hear anything from vhd(only computer screen). With _super0/2/3 i can hear the audio from vhd but no picture(only computer screen).
And by the way, ctrl+f5 (supeimpose shortcut) does not work for me, it gives normal run command, but maybe that is because i use national cf3000 keyboard ?
It was color 15,0,0.
But also had to switch from default rgb connector composite input to separate composite input by pressing shift+ctrl+F2. And then change to superimpose mode by pressing then ctrl+F1. Then i got computer and vhd output, but vhd picture is really really dark(maybe have to change some capacitors from hc95 video parts). _super2 and _super3 basic commands seems to be same as that ctrl+F1.
Also those "set video" basic commands work.
So VHD interface is using addresses 0xBC-0xBF and 0xFFBC-0xFFBF for giving command/reading data.
when JVCREQ=1
--------------
A2=1
A3=1
A4=1
A5=1
A6=0
A7=1
so address is 0xBC-0xBF, so these are same I/O as in wiki page already.
when JVCREQ=0, then address must have these bits also:
A8=1
A9=1
A10=1
A11=1
A12=1
A13=1
A14=1
A15=1
so address is 0xFFBC-0xFFBF, these are not same as for Sharp X1 addresses mentioned in wiki page.
and for these addresses:
A1 A0
0xBC/0xFFBC 0 0 (8255 port A, data write/read from 80C49)
0xBD/0xFFBD 0 1 (not connected, so is not used)
0xBE/0xFFBE 1 0 (8255 port C, write commands towards 80C49?, read/write data?)
0xBF/0xFFBF 1 1 (8255 control register)
And for that 0xBE/0xFFBE the bits are:
0bxx
-bit0 = PC0 in 80C49C
-bit1 = not connected
-bit2 = not connected
-bit3 = INTQ1 output?
-bit4 = write to 80C49?
-bit6 = T0 in 80C49C
-bit5 = read from 80C49?
-bit7 = T1 in 80C49C
I hooked up logic analyser to vhd player and stored those four pins output 3,8,10,12 but not yet figured out how to decode data. Based on the blurry scramble basic listings and testing _vp command syntax trial and error, the frame number must be coming somehow through those pins. Frame number is inquired with _vp("g",T) , T is just what ever variable to store for basic. And if i could saw correctly, command _vp("g1234") would move disk to frame 1234. There is also _vp("n+1") or something like that? And _vp("h01")? Or _vp("c01")?
I also hooked up logic analyser to vhd card, but there was no activity for those pins 4,8,10,12 during giving those _vp commands. Maybe proper command would send command towards vhd player as same signal as the remote control signal would be like when decoded?
At least the data from vdh player, din13 pins 3,8,10,12 is just repeating (few different signal patterns repeat), so not including the frame number. This signal is sent for every field.
