The Commodore C16 really didn't sell very well in the United States because of the Commodore 64's pre-established success at when the C16 was released. It wasn't compatible with the C64's hardware or it's software. It lacked the SID (3 voice sound chip of the C64) and it's cost-reduced design intended for business use also lacked sprite capability. It does however have 121 colors. (The Commodore 64 has 16) and did in fact have a very good software library developed for it, in Europe. (PAL standard)
So time to upgrade the Commodore C16 to PAL using skills learned hours ago....
First up is the replace the NTSC video crystal, a 14.31818 with a 17.734475 (digikey part# 300-6038-ND)
The original crystal carefully removed.
Replaced with the new 17.734475
Naturally I also had to re-program the 27128 EPROM with the PAL version of the kernel.
(Bo Zimmerman's FTP site to the rescue here) Read older entries for how/why.
.... and ...
A working PAL Commodore C16!
Keep in mind that if you do this mod, you need to have a screen capable of handling the PAL signal from the Commodore C16. I'm using a Extron DVS 204 Digital Video Scaler which accepts both NTSC and PAL S-video signals and converts them to VGA. I'm using a MAG VGA CRT monitor which makes the signal look great.
Time to put this machine back together and grab some 16k PAL games to play while it continues to snow.
3 comments:
Hi Jeff,
I don't know if this applies to the C16, but I've heard that some PAL programs for the C64 check to see if the AC frequency coming in is 50hz or not. And if it's not, they won't run the program.
Good to see you online again. :)
John, aka "Rootboy"
The C16 runs entirely on DC & it's psu is entirely external so the C16 never sees the power line frequency at all, it's impossible on the 16. Nor does it happen on the 64 it has no way of measuring power frequency.
Au contraire CJ:
https://retrocomputing.stackexchange.com/questions/724/pal-c64-in-the-us-50hz-vs-60hz-ac-frequency-will-that-matter
Which shows the circuit that is used to create pulses from the 9VAC signal from the power supply that feeds in to pin 19 on the CIA chip.
I don't know personally of any programs that check the frequency, but I have heard of them.
And the AC frequency does indeed affect things like the music in games and Time of Day (TOD).
TIME is generated differently. So TIME has nothing to do with Time of Day. Go figure... :)
Pin 19 of the 6526 CIA chip is the TOD input pin where it gets either a 50 or 60 hertz signal derived from the 9 volt AC signal from the power supply. Some folks complain that the music on 50Hz PAL games sounds sped up on 60Hz. And there are ways to correct for this.
Probably something that is emulated on modern versions of the C64.
But the real iron definitely knows what your line frequency is.
Thanks for the response,
John
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