-----Oorspronkelijk bericht-----
Van: B. Wijnen <[EMAIL PROTECTED]>
Aan: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Datum: woensdag 27 september 2000 13:44
Onderwerp: Re: hardware question
Hi,
>Are you actually talking about analog MSX mice? I don't know about their
>existance (and I can't think of how they could be implemented, given the
>MSX hardware). So I shall stick to the digital MSX mice.
I'm not sure about this, but I think he wants to emulate a digital MSX mouse
through an analoge connection?
>The mouse is always in one of 4 states, which are degenerate in pairs
>(undistinguishable, or at least allmost). The mouse has 4 bytes of
>internal memory, 2 of which keep the X and Y movement since the last
>readout and 2 which are needed for output buffering.
>
>When the mouse is in state 0, the strobe is 0. This is the state it should
>be in when interrupts are enabled, and the mouse is not currently read
>out.
>
>Flipping the strobe to 1 sets the mouse in state 1. This causes the 2
>bytes of memory to be copied into the output buffers. After a little time,
>the low nibble of the X movement can be read out on pins 1-4 (up, down,
>left, right).
>
>Flipping the strobe back to 0 sets the mouse in state 2. This state is
>degenerate with state 0, because the MSX can only see the state of the
>strobe. While being in state 2, the pins 1-4 contain the high nibble of
>the X movement.
>
>The same thing can be done twice more. Flipping the strobe sets the mouse
>to state 3 and the pins 1-4 to the low Y movement nibble. Flipping it
>again returns the mouse in state 0 and leaves the pins 1-4 to the high Y
>nibble movement.
>
>A nibble is put on the pins 1-4 with MSb on pin 4 and LSb on pin 1, so it
>is in the correct order when read out by the MSX.
>
>I hope this helped you. If I didn't answer the question you meant to be
>asking, please rephrase it and I'll try again.
Thanks for this info! I'll forward this message to Padial. If he did mean
something else then I'll ask you again privatly, ok?
Greets,
Gerrit
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