Re: Apple ii projects for kids?

[Egan Ford <datajerk@gmail.com>]

On Sep 6, 10:56 am, sc...@alfter.diespammersdie.us (Scott Alfter)
wrote:
> In article <9a7a3e68-e48d-4d86-a382-c1ce280d5...@e8g2000vbc.googlegroups.com>,
> Kevin Dady  <ke...@hackaday.com> wrote:
>
> >yea, you can squeeze some GPIO out of the motherboard to twiddle
> >lights out other external systems, but I think you would need a card
> >on the II
>
> Only if you need more than 4 bits of output or 3 bits of input.  I
> implemented a 1-Wire controller in software that uses one bit each of input
> and output; source code and an ASCII-art schematic are here:
>
> http://alfter.us/computers/apple2/software.aspx
>
> "1-Wire Apple II Primitives" includes assembly-language code to bit-bang the
> joystick port and some BASIC examples to enumerate devices and read
> temperature sensors.  "Apple II Beer Fridge Controller" provides C code
> (with inline assembly where needed) that you can build with cc65; in
> particular, the C implementation of device enumeration is much faster than
> the BASIC implementation.
>
> (Just realized that the schematic provided with the beer-fridge controller
> code doesn't mention that a relay is switched on and off by AN1 (AN0 and PB2
> are used by the 1-Wire controller).  I just used a 2N3904 (or equivalent)
> for this purpose.  IIRC, connect the emitter to +12V, the collector to one
> end of the relay coil, and the base through a 1K resistor to AN1.  The other
> end of the relay coil is connected to ground.  A small diode should be
> connected in reverse bias across the relay to absorb back-EMF and keep from
> frying the transistor.)
>
>   _/_
>  / v \ Scott Alfter (remove the obvious to send mail)
> (IIGS(http://alfter.us/ ;          Top-posting!
>  \_^_/                              >What's the most annoying thing on Usenet?
>
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Scott, that's awesome.  We need to start a thread, "Apple ii project
for adults".  Although the kid suggestions look fun too.