Closed vitasam closed 3 years ago
I'm sure it's possible, just takes time and physical access to HW.
I have the HW, but have little knowledge about MPF-II modulation scheme. Do you have an idea where to start from?
connect it to audacity (FOSS, but perhaps get an older version now since there's spyware in the latest version, you'll have to google for tips on getting a non-spyware version), write some data, look at the waveform
Yep, I did it, it looks like there is 1 kHz of pilot signal, followed by probably frequency modulated signal (I see 2 periods of waves).
Looks like zeros and ones to me.
Hi, I just found from the manual, that MPF-II supports saving data to cassette in Apple-II format:
However, I'm not sure how compatible that format with an actual Apple-II format. Could you kindly take a look in to attached zip file, where 8 bytes ( 0400: 89 91 00 00 00 00 00 00
) have been stored to audio files (8-bit uncompressed PCM) from the real MPF-II computer? I was trying to generate the same mon's bytes to Apple-II .wav file with c2t, but MPF-II was not able to load that file.
Wow, it works!
0400: A2 00 BD 11 04 C9 FF D0
0408: 01 60 20 ED FD E8 4C 02
0410: 04 C8 C5 CC CC CF A0 D7
0418: CF D2 CC C4 8D FF FF 00
c2t-96h.exe -2 hellow.mon,400 hello.wav
CALL -159
400.41FRA
400G
excellent news
Thanks! By the way, do you know, is there a way to decode BASIC .wav file in to a text listing?
First you need to find a tool that will convert a basic binary dump to text listing. I do not know of any. Then you'll need to create a tool to read a wav and do the zero crossing detection so that you can extract the binary data for the 2nd tool; that should not be too hard, look at minimodem source as an example.
Yep, I guess such converter (BASIC binary to text) is a main problem. So, basically it should be a complete BASIC interpreter on a PC, able to load and list the program text.
About .WAV file - I'm using 1-bit .BAW format with ZXTapeRecorder2 device, it works very reliably with MPF-II (after HW modification of MIC port). My guess is that 1-bit format should be relatively easy to convert into binary dump.
Hello, what do you think is possible (in theory) to do the same for this Apple-II clone? https://en.wikipedia.org/wiki/Microprofessor_II
I was not able to find any information about cassette data format of MPF-II, but comparing WAV files from Apple-II and MPF-II, it becomes clear that they are different.
Do you think it would be possible to reverse engineer an audio file from MPF-II if, for example, save a block of memory from Monitor with known bytes to a file?