Alex Wulms wrote:
>
> On MSX models without a buffer circuit between the MSX engine and the
> joystick port, you can even blow up your whole MSX engine. And those models
> do exist!
>
> Kind regards,
> Alex Wulms
>
ALL MSX computers I saw (including Panasonic A1 , A1F , A1ST & A1GT)
DO NOT have any buffers on the joystick port. The inputs goes directly
for the MSX Engine , or in cases of machines built with discrete logic
the lines goes for a pair of 74LS157 chips and from these chips goes
for the PSG data port.
If the machine have a MSX Engine, the 74LS157 logic is inside the
engine. The manufacurers do put a dual line of non polarized protection
zeners. But I think that�s protection only for static eletricity ...
I'm sure that if you all don't hear Mr. Wulms you all may get burned
joyports ... =(
Maybe it's time to add buffers & protection logic to such circuits ...
Cya MSXers ...
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