Emulation questions

[carlsson]

Did I do a load of CLOAD? Hm, can't remember. CreatiVision BASIC anyhow loads and saves ASCII files, each row is reversed from right to left if I recall correctly.

[@username@]

have you made new version? I ask because you have not attach one. For the CLOAD and CSAVE i know that Carlson do a lot with this and TOM who build the interface for Commodore Tape.

The link is pointing to 21:03 31-10-2013 - so maybe cache ? Retry and if it still fails, I'll build a new one later.

On CSAVE I have determined, at least, how it interacts with the PIA. When all bits are OUTPUT on PIA 0, it's writing to the cassette. The pulse width is 142 iterations for 1, 64 for 0. Now to try to see how it 'encodes' the data for tape.

[Mobsie]

i have the new emu version, its great! I test all parameter and test some games and demos. The sound is really clear now.
Please don`t stop your work

[@username@]

Ok, more news on CSAVE. The basic protocol for saving is:

Code: Select all

Send Header - 1024 bytes of zeros
While data to send
{
  Send Packet Header - 13 x 0x10000 followed by 0x1110110 - (that is 17 bits x 13 followed by 7 bits)
  Send in block of 64 characters backwards ($26F-$230)
  Send single byte checksum, generated by adding the characters up.
  Single NULL byte
}

No output for 3 seconds,

Send Packet Header
Send Packet of 64 Nulls
Send Packet Header
Send Packet of 64 Nulls

Knowing this, it's possible to CLOAD data to a real creatiVision through a PC soundcard, once the actual speed and levels are agreed. Sadly, I'm no hardware guy, so you'd need someone who knows about the connections to make sure any home made cable would not do any damage. Of course, once that's established, CSAVE back should work too! We could even try to work out the audio tapes, so you can listen to Fall Out Boy while it loads

[Mobsie]

Thats interesting, we do this on the Enterprise 128 (the 8-Bit Monster). We connect to PC soundcard and use a tape-emu software to load the tape as .wav etc.

[Mobsie]

I forget, please read that from Tom: viewtopic.php?f=10&t=14

[@username@]

I forget, please read that from Tom: viewtopic.php?f=10&t=14

Nice read. It confirms some of what i was thinking. It is possible with that box to get the levels right on your wav recording. The loading at higher speed also makes sense, as it's just a locked loop, once it triggers at the packet header - it can be as quick as the software can go!

Update : CSAVE, CLOAD and CRUN now working in native mode!!!

I can also confirm that the emulator can load at up to 2x - so I'd assume a real machine can too.
I'm going for CVB file format - which is essentially just the raw bit data.

@mobsie
Here's a link to the latest build, which now includes a txt2cvb utility. There's a new command line switch, -l, which doubles the loading speed.
Thanks again!

[Mobsie]

GREAT!
Works perfect. I make a quick test of all. Today i will check deeper. After i finish one of my games, i will continue with my Basic hack. I have near the complete source and have also integrate a basic command to call bios functions. At the end is a normal SYS command like on the VIC-20 and can be used for "very little" assembler routines. This together with your emu must bring a lot fun and the CV is then a real computer.

[@username@]

Ok, I've written the cvb2wav too - just need to wait for someone with an audio box to see if it's any use.

I think for the most part, the emulator is done. The only program giving trouble is DIAGV, which uses undocumented modes on the VDP, Mode 5???

So, I'll post up the source after I clean it, if you're ok taking a look and maybe having a try on OSX.

Thanks again! - Look forward to the BASIC SYS stuff.

[Mobsie]

perfect!
The undocumented modes are not so important i think because all this modes have some negative sides. The half-bitmap mode for example give us only 8 error free sprites. I use this mode in a demo and it runs only on real CV.