Michael J. Mahon (mjmahon@aol.com) writes:
Eric wrote:
Echo II+ has the capability to produce stereo sound effect (the 2 x
AY-3-8913 chips) and speech (TSP5220 chip) I think.
However, I have not seen any games or software take advantage of the sound
effect.
Don't think you can play Apple II sound thru the Echo card, but you can play
echo sound through the internal speaker using the 2-pin connector (labelled
as "Apple Spkr" on the card) connect to the motherboard.
My Echo+ card has a stereo and a mono speaker output, but no inputs
and no 2-pin connector (just 1/8" mono and stereo phone jacks).
While it has the same sound generators as the Mockingboard, they
are both controlled by one 6522 (while the Mockingoard uses two),
so it is not compatible with the Mockingboard at the hardware level.
FWIW, it surprised me when I saw that the Mockingboard used two
6522s to control two 8910s. Each 6522 has two 8-bit ports, and one
would have sufficed. (Of course, another would have been required to
add speech, then.) It seems that the Mockingboard was simply a
"doubled" mono design. The early models even brought the "extra"
8-bit parallel port of the 6522 out to a header on the card.
-michael
I remember at least one article in the hobby computer magazines
that used that sound generator, and then used more than one PIA
to controll it. I forget the exact details, but it struck me
at the time that whoever designed it did not understand the sound
generator. Admittedly it is an odd interface buss, not so useful
for connecting to the average CPU bus directly (hence the need for
something like the 6522), but it is intended for connecting to
some sort of buss, meaning most of the pins can be put in parallel
with only a separate address pin of some sort (it's been a while
since I looked at the pinout). You're right, that board did
not need two 6522's.