söndag 25 januari 2009

Getting the pieces togheter...

- Saving files to WAV and to MD and MP3 players.
My "boom-box" doesn't have any recording input. This is the only existing cassette-player at home. The rest; such as Walkmans, my very first Philips recorder from 1970(?) and even the HiFi stereo tapedeck are gone for ever.
So, what about recording files to todays digitatised formats such as MP3, WAV and MD?
Read somewhere that MP3 wouldn't work and I dropped that alternative immediately.
Archieving all the audiofiles to WAV was easy, a freeware recorder and a cable between PC and tape. Recording was done in 22 kHz, 8 bit mono to be compliant with the KCS08 encoder/decoder program for the ancient Kansas City and CUTS formats, if any decoding should be needed. For fun, I tested the KCS decoding and also encoding and it worked. Great utility!
--MD: (Sony ATRAC) works very well, both in loading and saving. No dropouts at 600 baud were discovered.
The disadvantages are the proprietory audio-only format, it's is not a file directly recognized by Windows (needs decoding), needs specific media and that my old player (MZR30 from 1998) is somewhat "clumpsy".
-- WAV: (recorded on a iAudio U2 MP3 stick) also works well, although more sensitive when it comes to recording levels, at least at 600 baud. The stick is of course more convinient and more self-contained. Also the possibilities of file management in Windows for archieving etc is better.
Will try to increase the recording level on the UK101 by changing the resistor-network at the output.

- The PIA and future troubleshooting
I built the PIA (parallell interface adapter, based on 6821) in the early 80's and it worked well.
At least it could drive LED's, indicating output and proper function. I don't remember testing input on the other hand.
I bought two extra 8T28 IC's from Philips Sweden (a long story itself...) as buffers and but they were'nt needed in this case. Instead I jumpered the sockets (U6, U7). For trivia, the 8T28 were stolen, along with a lot of other electronic stuff, in a inbreak in my shed 1996.

The interfacing was rather easy. Instead of building an external interface with addressing logic, I used one spare output of IC17 address decoder (also controlling the ACIA) plus did some trace-cutting on the board (for connections to PIA chipselect and +5V)

One project for the PIA was a EPROM programmer and I did some programming for it, but time and interest lacked at the end.

During the restoration work I found that the PIA "hangs" the UK101, in other words stops executing. Will do some troubleshooting on this when some sparetime shows up! Could be a short or perhaps a bad 6821.
Scoping the signals, at the socket and at the 6821 shows no "ratty" data or signals.
Well, the good news is that 6821 is still available as new as well as surplus, if needed.

- New version of the File Manager planned!...
The tool for further development in assembler is the below freeware that has proved to be very good!

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