Michael Karas wrote in message
...
[This followup was posted to sci.electronics.repair and a copy was sent
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In article ],
says...

In article , "N_Cook"
wrote:

isw wrote in message
]...
In article , "N_Cook"

wrote:

A very useful cheap and cheerful IR remote control is let down by
somewhat
inadequate memory.
http://www.amazon.co.uk/
7dayshop-Universal-Control-Learning-Function/dp/B0043VTRAQ

it uses a 24LC32B
Is it likely or unlikely that if I changed it to a 128, that the
firmware on
the ucontroller would limit the running to 32K/ not work at all or
allow
running out to 128K ?
As serial linkage I'm hoping it would not be limited

If it can't address more memory, you could use two (or three) memory
chips with a switch to select which one to use.

Isaac

What would be the minimum number of lines that would need switching ?
Could you leave A0,A1,SDA paralleled and just switch SCL and WP?

Check what the data sheet says ...

Isaac

The original design has the A0 and A1 pins tied off in some particular
state (most likely at GND). You could arrange your additional chips with
all connections in parallel except for the A0 and A1 pins. Your
switching could the simply be setup to present just one chip at a time
with the A0 and A1 pins set to levels that match the original design.
This way that would be the chip to respond when the controller chip
sends out the I2C slave address.

Supporting two chips like this has trivially simple switching of just
one of the addressing lines. Just make sure that you _do_ _not_ ever
have two or more chips with the A0 & A1 levels being the same and
matching the original design settings.

--

Michael Karas
Carousel Design Solutions
http://www.carousel-design.com



So any switching has to be break before make combined with gating off all
switching while any activity