Post by thread: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 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.

> 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_OUTthomasTakeThisOuTadvancedcontrol.com (208) 362-5858

> 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.

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. > >

Dr. Imre Bartfai wrote: > > 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. the full source and hex file can be found at: http://www.dontronics.com/see.html This is part of the On-line version of the Scott Edwards Electronics Pic source book for the Basic Stamp 1. Don McKenzie .....donKILLspam@spam@dontronics.com http://www.dontronics.com Don's Download Dungeon: http://www.dontronics.com/download.html For more details, send a blank message to infoKILLspamdontronics.com or .....simstickKILLspam.....dontronics.com or EraseMEbasicsspam_OUTTakeThisOuTdontronics.com

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:ghagerspam_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.

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@vmkKILLspamreal.kiev.ua, Kiev, Ukraine.