Post by thread:[EE]: tri-state interface to 12vdc CMOS logic

Hi. I'm looking for a buffer/line driver that i can use to interface a PIC to some 12vdc CMOS (14000 series) logic. It needs to be able to read and write from/to the same 4 CMOS i/o lines. Only a single output enable is needed. The state will change on the order of hours so speed isn't much of an issue. Preferably all in a single DIP package. After hours of searching i've found nothing but a lot of chips that don't look like they'll work... Help, -Craig -- http://www.piclist.com hint: To leave the PICList spam_OUTpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

7406 / 7407 These are open drain gates that will accept a 5V logic input and output whatever voltage you wish. Often used for logic- to-motor/sensor/etc. They function in a similar way to Porta.4 on the F84/628 Those that you want to read, simply set their output voltage to 5V, and limit their inputs to 5V with a zener or resistive divider. Those that you want to drive can be done so directly and their outputs will assume the voltage (12V) that you pull them up to They are very useful ICs. Read the spec sheet here http://www.philipslogic.com/products/buffers/06/ Some others you could consider http://www.philipslogic.com/products/levelshifters/ Bookmark this http://www.philipslogic.com/products/ Other options would be the micro-to-PC interface chips such as MAX232, MC1488/1489 derivatives, or any of the level shifters used in comms circuits -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam@spam@mitvma.mit.edu

At 08:49 AM 2/26/02 +1300, you wrote: >Hi. >I'm looking for a buffer/line driver that i can use to interface a PIC to >some 12vdc CMOS (14000 series) logic. It needs to be able to read and >write from/to the same 4 CMOS i/o lines. Only a single output enable >is needed. The state will change on the order of hours so speed isn't >much of an issue. Preferably all in a single DIP package. Hey, have I got the chip for *you*! http://www-s.ti.com/sc/ds/cd40109b.pdf No external parts, one 16-pin DIP and reasonably fast. Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" speffKILLspaminterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com 9/11 United we Stand -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam.....mitvma.mit.edu

> http://www-s.ti.com/sc/ds/cd40109b.pdf > > No external parts, one 16-pin DIP and reasonably fast. Spehro, I inadvertently missed the need for tri-stating, yours looks to be more applicable than my suggestion and I'm sure there will be equivalents at other mftrs -- http://www.piclist.com hint: To leave the PICList EraseMEpiclist-unsubscribe-requestspam_OUTTakeThisOuTmitvma.mit.edu

At 11:54 AM 2/26/02 +1300, you wrote: >and I'm sure there will be equivalents at other mftrs In fact, Jinx, the link to a Philips page that you provided looks to contain some products that would be useful here. These level shifters seem to have a lot of part numbers, if it was my design I'd be looking carefully at long-term availability, maybe allowing for two types... Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" speffspam_OUTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com 9/11 United we Stand -- http://www.piclist.com hint: To leave the PICList @spam@piclist-unsubscribe-requestKILLspammitvma.mit.edu

For slow signals use a quad opamp like a LM324 (I did this). You will use a reference of 2.5V. This only works for output. It can be made to work backwards but it will need too many parts. The opamp is used as comparator (no feedback). hope this helps, Peter -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads