usually, you can use lcd's in 4 bit data mode. if you don't need to read data from the lcd (usual case), you can connect the rw pin to gnd. so you get 5 i/os back. tino Jai Dhar Gesendet von: pic microcontroller discussion list 11.04.03 15:47 Bitte antworten an pic microcontroller discussion list An: PICLIST@MITVMA.MIT.EDU Kopie: Thema: Re: [PIC]:Utilizing I/O Ports in PIC with requirements for Interrupt and Low I/O Count Since it seems that you need Port B for all of this, try using a serial in/parallel out shift register for the LCD. You could use the 3 control bits on another port if you wish, and use the shift register for the 8-bit data bus. That would only take 2 pins of port B there, leaving 6 for the buttons or your encoder. Quoting "Mccauley, Daniel H" : > Hello. I am currently working on a PIC project which will utilize a wide > variety of I/O which is listed below: > > Hitachi Controlled LCD (8-Bit Data + 3-Bit control bits) > (2) Pushbuttons (which will need wake-on-keystroke capability) > (2) Optical Encoder quadrature inputs - Which will require using RB0 > Interrupt. > > I am currently looking at using the PIC16C6x series of microcontrollers in > particular the PIC16C66 since I can add a 32.768kHz clock at T10SI and T10SO > to provide > an internal counter capable of keeping high accuracy seconds. > > My question is, what is the most effective way to configure my I/O with the > above requirements. Can I keep the 8-Bit data bus on Port B, and at the > same time > use Port B also for my two pushbuttons (R4-R7 for interrupt on input change) > and also have my Optical Encoder's first bit on RB0 for an external > interrupt? > > Any help appreciated. Thank you. > > Dan > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > ---------------------------------------- This mail sent through www.mywaterloo.ca -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu