Look at a 74xx chip called the 74HC259. It is a latching 3-line to 8-line
decoder/demultiplexer. Here is the pinout:

1) A0 (The address select lines)
2) A1
3) A2

4) Q0 (The outputs)
5) Q1
6) Q2
7) Q3

8) Gnd

9) Q4 (The outputs cont.)
10) Q5
11) Q6
12) Q7

13) D (data input)

14) LE_ (Latch Enable active low) (The control lines)
15) MR_ (Master Reset active low)

16) Vcc

More information on this chip is available from Phillips at
http://www-us.semiconductors.philips.com/handbook/chapter_1906.html

The idea is that the a0-a2 lines on the '259's will be bussed together along
with the data line. The latch-enable lines will be wired individually(for
your application you will need 2 bits on your output port); the MR_ input
will be disabled (The device can be cleared by writing 8 zeros in a loop -
this will save you a pair of pins on your PIC). This is a total port usage
of 6 bits to latch and light 16 bits of LED's.

Good luck - Keith Causey

I think you need something called a Bar Graph driver.
Not just a simple N to 2^N driver, though :(

GL,
Walt...

-----Original Message-----
From: Vernon Bradshaw [mailto:WVBradshaw@WORLDNET.ATT.NET]
Sent: Thursday, January 06, 2000 5:58 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: More than 8 LED's from a single 8-bit port


Is there a way to illuminate more than 8 LED's using a single 8-bit
port. I am tryin to have a block of ten LED's increase or decrease by
one when I press either an up or down button.

Thanks,

Vern Bradshaw
WVBradshaw@worldnet.att.net