On Thu, 22 Jun 2000, Leonard Silva de Oliveira wrote:
> Some time ago I noticed that Turbo-R machines does that with all MSX
> system
> reserved I/O port ... Then if you try to read any I/O port that has a
> internal
> pehiperal installed the S1990 chip engine will block output from the
> cartridge.
> I guess it's made this way to avoid "totem pole" (bit conflicts) of
> S1990
> internal buffer with the internal machine devices such as PPI, VDP,
> PSG , Mapper, etc ....
I don't think this is true. For example, Padial's PC keyboard interface is
inserted in an external slot and acts like a partial PPI. And ofcourse it
supports all keys, not just the ones in columns 0 to 4 (lower 5 bits).
Bye,
Maarten
****
MSX Mailinglist. To unsubscribe, send an email to [EMAIL PROTECTED]
and put "unsubscribe msx [EMAIL PROTECTED]" (without the quotes) in
the body (not the subject) of the message.
Problems? contact [EMAIL PROTECTED]
More information on MSX can be found in the following places:
The MSX faq: http://www.faq.msxnet.org/
The MSX newsgroup: comp.sys.msx
The MSX IRC channel: #MSX on Undernet
****
