RE: Re: [Development] Lights, using two micros.

["Keith Doxey" <ukha@xxxxxxx>]

As long as the PIC is in a socket (3 pence) which is adviseable incase you
need to upgrade the PIC at a later date, the only extra is shoving a
different PIC into the socket when you assemble it. Would take less time
than fitting the jumper pins and putting the links on the pins.

There isnt really much difference in programming between

400 x Dimmer Chip
or
100 x Dimmer A Chip
100 x Dimmer B Chip
100 x Dimmer C Chip
100 x Dimmer D Chip

This also holds true for larger numbers because the PIC is chaper than a
programming switch for setting the address.

When we move onto the keypad project, address programming can be done via
software. Many devices have *secret* keypresses such as holding two buttons
pressed for 5 seconds to enter programming mode. In this case we have very
few pins to start with and the address would only need to be set once. If
it
ever needed a different address simply change the PIC. This is only a
channel address within a controller. The main addressing funcions are
handled by the controller.

As John said, you could do away with the address altogether and drive each
one from a seperate pin on the Rabbit but that is wasting valuable pins on
the Rabbit.

Many TV chips use I2C bus where 2 lines drive upto 8 chips in the TV. this
allows a microcontroller to interface with other complex devices without
having to use lots of pins.

Keith


-----Original Message-----
From: Jon Whiten [mailto:jon@xxxxxxx]
Sent: 03 June 2001 19:31
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] Re: [Development] Lights, using two micros.


We use _alot_ of 12C508 micros so with a bit of luck may be able to get
these at cost.

Whilst I like the idea of hard-coding an address into the PIC, this does
add
another operation/stock-line to productionising the product and hence an
added cost.  Depends, of course, on quantity though.

Regards,

Jon
+--------------Personal------------+----------Work-----------+
Jon Whiten        Church Gresley   D.G. Controls Limited
Derbyshire  Beacon Lamp Specialists
jon@xxxxxxx         England      mail@xxxxxxx
http://www.whiten.co.uk/          
http://www.deegee.com
+----------------------------------+-------------------------+



> -----Original Message-----
> From: Keith Doxey [mailto:ukha@xxxxxxx]
> Sent: 03 June 2001 10:22
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] Re: [Development] Lights, using two micros.
>
>

> Allows 4 different PIC addresses on one serial line from Rabbit
> PIC 12C508 or 12C509 is about 70pence. It would do almost all the work
in
> the dimmer.
>




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