Searching \ for '[PIC]: Expanding PIC I/O' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/ios.htm?key=i%2Fo
Search entire site for: 'Expanding PIC I/O'.

Exact match. Not showing close matches.
PICList Thread
'[PIC]: Expanding PIC I/O'
2002\08\01@105555 by Trevor Page

flavicon
face
Hi list.

I have an application where I need to generate a relatively large number of
(slow) PWM signals. I'm not sure how many at the moment, but we could assume
this number would far exceed the number of available IO on a PIC. Actually,
the fact that it is PWM is probably not relevant. Let's just say that I need
to expand the IO of my PIC. I don't need bi-directional IO. All I want to do
is generate a large number of PWM signals, which will be low-pass filtered
to get some crude analogue control voltages.

The most obvious solution to me at the moment is through the use of a number
of octal / hex latch ICs, such as the 40174. On the other end of the scale,
I could use a Xilinx CPLD if I wanted to go mad (and needed the speed, which
I don't).

Can anyone suggest their own favourite solution for expanding IO on a PIC,
to get a large number of digital outputs? Any particular device I should
consider looking at?

Thanks in advance,

Trevor.

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\08\01@112119 by Byron A Jeff

face picon face
On Thu, Aug 01, 2002 at 03:55:07PM +0100, Trevor Page wrote:
> Hi list.
>
> I have an application where I need to generate a relatively large number of
> (slow) PWM signals. I'm not sure how many at the moment, but we could assume
> this number would far exceed the number of available IO on a PIC. Actually,
> the fact that it is PWM is probably not relevant. Let's just say that I need
> to expand the IO of my PIC. I don't need bi-directional IO. All I want to do
> is generate a large number of PWM signals, which will be low-pass filtered
> to get some crude analogue control voltages.
>
> The most obvious solution to me at the moment is through the use of a number
> of octal / hex latch ICs, such as the 40174. On the other end of the scale,
> I could use a Xilinx CPLD if I wanted to go mad (and needed the speed, which
> I don't).
>
> Can anyone suggest their own favourite solution for expanding IO on a PIC,
> to get a large number of digital outputs? Any particular device I should
> consider looking at?

The 74HC595 is a popular choice. 8 latchable, tristatable outputs that are
serially loaded. Can be laid end to end to create a large number of outputs.
Any number of outputs can be controlled by 3 PIC pins (data,clk,latch).

BAJ

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\08\01@200538 by Michael Rigby-Jones

flavicon
face
{Quote hidden}

You could consider another PIC that is dedicated to the PWM and has a
two/three wire interface to your main controller.

Regards

Mike

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\08\01@211306 by Mike Singer

picon face
Michael Rigby-Jones wrote:
.
> You could consider another PIC that is dedicated to the PWM and has a
> two/three wire interface to your main controller.
.
Yes! PCB can carry double! :-)

Mike.

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


More... (looser matching)
- Last day of these posts
- In 2002 , 2003 only
- Today
- New search...