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Thread
'Any Ideas to add more Ports ????'
1998\07\20@134631
by
Ricardo Ponte G
I«m working with the PIC16C715. It has 13 I/O lines but I got to
manipulate one LCD, read some extern values and control some devices.
I just want to be sure about the best way that I can add some I/O lines
(Ports) with other devices like 82C55, because I«m not sure now if I«m
going to need it.
What good device can I use with this PIC to add one or two Ports of 8
lines ?.
and with the LCD stuff:
What way is better: control it with 4 bit mode or 8 bit mode ?
Thanks to the peoples that can help me out with this.
1998\07\20@164930
by
thomas
> I«m working with the PIC16C715. It has 13 I/O lines but I got to
> manipulate one LCD, read some extern values and control some devices.
>
> I just want to be sure about the best way that I can add some I/O lines
> (Ports) with other devices like 82C55, because I«m not sure now if I«m
> going to need it.
>
> What good device can I use with this PIC to add one or two Ports of 8
> lines ?.
>
A 16C74 has more I/O.
Another idea is to use AN541 to program a 16C5x as a I2C
peripheral.
> and with the LCD stuff:
>
> What way is better: control it with 4 bit mode or 8 bit mode ?
I've found the 8-bit mode to be a little more reliable.
> Thanks to the peoples that can help me out with this.
>
Thomas J Macauley, KD7BDW
spam_OUTthomasTakeThisOuT
advancedcontrol.com
(208) 362-5858
1998\07\20@175214
by
org Hager
> I´m working with the PIC16C715. It has 13 I/O lines but I got to
> manipulate one LCD, read some extern values and control some devices.
>
> I just want to be sure about the best way that I can add some I/O lines
> (Ports) with other devices like 82C55, because I´m not sure now if I´m
> going to need it.
>
> What good device can I use with this PIC to add one or two Ports of 8
> lines ?.
>
A good way to get more output lines is to use shift registers like the
CD4094. You need 3 lines to control it (or two, if you do it in a clever
way) and get 8 output lines in return. If top speed is not an issue, this
is surely a cool solution.
Georg.
1998\07\21@023538
by
Dr. Imre Bartfai
|
Hi,
I have had similar problems. I can recommend the so-called Port Expander
(Stretcher). It is not other than a PIC16C57, already programmed, at us it
costs $3. Its firmware has an one-line serial bus (2400 baud; it is the
limitation), and you can control so additional 16 port bits (the full B
and C port of it). It is cheap and nice. My PIC design uses 4 MHz and with
this xtal I can drive also the said 16C57. AFAIK it is made by Parallax.
It is the ideal solution until you need speed.
Imre
On Mon, 20 Jul 1998, Ricardo Ponte G wrote:
{Quote hidden}> I«m working with the PIC16C715. It has 13 I/O lines but I got to
> manipulate one LCD, read some extern values and control some devices.
>
> I just want to be sure about the best way that I can add some I/O lines
> (Ports) with other devices like 82C55, because I«m not sure now if I«m
> going to need it.
>
> What good device can I use with this PIC to add one or two Ports of 8
> lines ?.
>
> and with the LCD stuff:
>
> What way is better: control it with 4 bit mode or 8 bit mode ?
>
> Thanks to the peoples that can help me out with this.
>
>
1998\07\21@035752
by
Don McKenzie
1998\07\21@045529
by
Steve Lawther
|
Also, remember that you've 4 or 8 lines (10 in you push it to the
extreme) to the LCD that can be used for other stuff when LCD
enable
is low.
So assuming the LCD is using 8 bit mode, just connect up to an 8
bit
latch (HC573 ish - LE connected to LCD enable low AND LCD write
high)
and / or an 8 bit buffer (244 ish - OE# connected to NOT ( LCD
enable
low AND LCD read high)) and you get 8 O/Ps and / or 8 I/Ps, needing
no
extra I/O pins on the PIC.
The advantage over shift registers, is that no shift routine is
needed.
Steve Lawther
______________________________ Reply Separator
_________________________________
Subject: Re: Any Ideas to add more Ports ????
Author: Georg Hager [SMTP:ghager
spam_OUTTHEORIE3.PHYSIK.UNI-ERLANGEN.DE] at
UKExchange
Date: 20/07/98 22:50
> I«m working with the PIC16C715. It has 13 I/O lines but I got
to
> manipulate one LCD, read some extern values and control some devices.
>
> I just want to be sure about the best way that I can add some
I/O
lines
> (Ports) with other devices like 82C55, because I«m not sure now if I«m
> going to need it.
>
> What good device can I use with this PIC to add one or two
Ports of 8
> lines ?.
>
A good way to get more output lines is to use shift registers like the
CD4094. You need 3 lines to control it (or two, if you do it in a clever
way) and get 8 output lines in return. If top speed is not an issue,
this
is surely a cool solution.
Georg.
1998\07\28@020134
by
Vladimir M. Klochko
Hi!
20-Jul-98 13:38 Ricardo Ponte G wrote about "Any Ideas to add more Ports ????":
>> I'm working with the PIC16C715. It has 13 I/O lines but I got to
>> manipulate one LCD, read some extern values and control some devices.
>>
>> I just want to be sure about the best way that I can add some I/O li
nes
>> (Ports) with other devices like 82C55, because I'm not sure now if I'm
>> going to need it.
>>
>> What good device can I use with this PIC to add one or two Ports of
8
>> lines ?.
CD4094 was mentioned as a solution for output. It's
disadvantage is a relatively low output current.
CD4014 and CD4021 can be used for input.
>> and with the LCD stuff:
>> What way is better: control it with 4 bit mode or 8 bit mode ?
You are short in I/O pins. So 4-bit mode is the *best*. :)
--
Vladimir M. Klochko
@spam@vmkKILLspam
real.kiev.ua, Kiev, Ukraine.
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