Post by thread:[PICLIST] [OT] Port Expander IC

Hi everyone, I am using the PIC16F877 and I now run out of I/O port. I want to have 10 or more I/O pins. The only thing I can think of is using the HC595 and HC165 for port expansion thru the SPI, but neither of them is bidirectional. I want expanded bidirectional I/O port! Is there any Port Expander IC out there that is bidirectional? Is there any other way to expand I/O ports? Please help! Thank you in advance! Thomas _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> -----Original Message----- > From: Thomas N [spam_OUTthomasn101TakeThisOuThotmail.com] > > Hi everyone, > > I am using the PIC16F877 and I now run out of I/O port. I > want to have 10 > or more I/O pins. The only thing I can think of is using the > HC595 and > HC165 for port expansion thru the SPI, but neither of them is > bidirectional. > I want expanded bidirectional I/O port! Is there any Port > Expander IC out > there that is bidirectional? Is there any other way to > expand I/O ports? > Please help! Try Philips PCF8574 or 8575, they are I2C I/O expanders and they can generate an interrupt on change. -Mike -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

>Is there any Port Expander IC out >there that is bidirectional? Is there any other way to expand I/O ports? >Please help! I do not know if the port expander for the Intel 8041 series micro's is still available. It was called a 8343 from memory. It had 4 x 4 bit ports, but from memory it would take a little bit of bit bashing to make it work. Should not be hard to do, just some more software, but it would take 5 or 6 pins from your 877 to drive it. It had some nice features like being able to do logic operations with the selected port. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

Try pcf8574 I2C Bi-directional port extender. Only 2 lines required and you can have 8 x 8 extra i/o lines if u use 8 x pcf8574 chips. Cheers Johan Pretorius E-mail : johanp2KILLspamtransnet.co.za > {Original Message removed}

Try pcf8574 I2C Bi-directional port extender. Only 2 lines required and you can have 8 x 8 extra i/o lines if u use 8 x pcf8574 chips. {Original Message removed}

Pretorius, I will get the PCF8575. This guy has 16 I/O pins. Why do I have to use 8 x PCF8574 chips while I can use 4 x PCF8575 chips? Thomas >From: Pretorius Johan * Spoornet <.....JohanPreKILLspam.....SPOORNET.CO.ZA> >Reply-To: pic microcontroller discussion list <EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU> >To: PICLISTspam_OUTMITVMA.MIT.EDU >Subject: Re: [OT] Port Expander IC >Date: Tue, 10 Apr 2001 11:46:32 +0200 > >Try pcf8574 I2C Bi-directional port extender. Only 2 lines required and you >can have 8 x 8 extra i/o lines if u use 8 x pcf8574 chips. > > > {Original Message removed}