8-to-256 decoder/demultiplexor possible?
8-to-256 decoder/demultiplexor possible?
(OP)
um im building a computer interface and im using 1 of the contorl lines to turn the interface into "card select mode" wehre the 8 bits of the data select teh card, i want to be able to have 256 cards so i need a 8-256 demultiplexor to select the card based on the value of the data lines
Does this chip exist, if not how can i rig up a series of chips to do the same
Thanx in adave
Does this chip exist, if not how can i rig up a series of chips to do the same
Thanx in adave





RE: 8-to-256 decoder/demultiplexor possible?
If need more, send FAX#
<nbucska@pcperipherals.com>
RE: 8-to-256 decoder/demultiplexor possible?
Beyond that size it starts to get complicated!
RE: 8-to-256 decoder/demultiplexor possible?
RE: 8-to-256 decoder/demultiplexor possible?
RE: 8-to-256 decoder/demultiplexor possible?
Check Altera or Xilinx.
Dean.
RE: 8-to-256 decoder/demultiplexor possible?
too expensive -- not to speak about software cost and
learning time...
<nbucska@pcperipherals.com>
RE: 8-to-256 decoder/demultiplexor possible?
with appropriate pullup resistors, and the 8 address bits to port B. The software
compares the two, and when they are equal, it outputs a pulse from port A. I
have a STROBE bit tied to one pin on port A, so it only triggers when I want it to.
Otherwise, it could be decoding while bits are still flipping on the bus.
With this method, I am able to decode three different addresses per chip, so I can
have multiple, separate functions on the same card. I use the pulse from port A
to trigger a data latch, or a DAC with internal latching bus interface, or the enable
line on a 4-16 decoder.