Post by thread:DS1990 (DalSemi iButton), anyone?

Hello all, Has anyone looked into using the iButton cans (http://www.ibutton.com) from Dallas Semi? They use a 1-wire interface which probably would work with a PIC, though there may be some issues dealing with the 115kbit/sec transfer rate. These things seem like a great application of the PIC, which could provide a gateway to real-world elements using the DS1990 as an authentication tool. Am I totally wrong here? Sorry, I've been lurking in this group for a while, and haven't made the leap from Stamps to PICs, so I'm not really familiar with the throughput possible with an entry-level PIC. Thanks, Nathan

Nathan Schmidt wrote: > > Hello all, > > Has anyone looked into using the iButton cans (http://www.ibutton.com) from Dallas > Semi? They use a 1-wire interface which probably would work with a PIC, > though there may be some issues dealing with the 115kbit/sec transfer rate. > These things seem like a great application of the PIC, which could provide > a gateway to real-world elements using the DS1990 as an authentication > tool. Am I totally wrong here? Sorry, I've been lurking in this group for a > while, and haven't made the leap from Stamps to PICs, so I'm not really > familiar with the throughput possible with an entry-level PIC. > I already done that . if you need any info , code or such stuff drop me a line btw the 115 kbit /s is not a big deal because you literally have to pull every single bit out of that can . so it's as fast as you wish it to be . at 4MHZ a pic16c84 can handle all the protocols needed by those little creatures if you don't need many button online even the addressing can be stored in eeprom bye charley

hoss karoly wrote: > I already done that . > if you need any info , code or such stuff drop me a line > btw the 115 kbit /s is not a big deal because you literally have to pull > every > single bit out of that can . > so it's as fast as you wish it to be . at 4MHZ a pic16c84 can handle all > the > protocols needed by those little creatures > if you don't need many button online even the addressing can be stored > in eeprom > > bye > charley Hey Charley, I'd realy like to see that also please. email me at my provate e mail address, to keep the noise level down on the maillist. thanks Peter....... Email spam_OUTefocTakeThisOuTcyberstop.net ================================== = New Ideas come from those who = = didn't know it wasn't possible = ==================================

According to Nathan Schmidt: > > Hello all, > > Has anyone looked into using the iButton cans (http://www.ibutton.com) from Dallas > Semi? They use a 1-wire interface which probably would work with a PIC, yes tho not from a PIC. We use the buttons for tracking people in radiation work areas (a requirement of NRC). People touch into and out of work areas. the buttons are read by a videx reader which stores the info until a pen-top harvests the data-- works great & was much cheaper that other alternatives we looked at. You and also read them from a PC serial port so a PIC shouldn't be much of a trick. {Quote hidden}> though there may be some issues dealing with the 115kbit/sec transfer rate. > These things seem like a great application of the PIC, which could provide > a gateway to real-world elements using the DS1990 as an authentication > tool. Am I totally wrong here? Sorry, I've been lurking in this group for a > while, and haven't made the leap from Stamps to PICs, so I'm not really > familiar with the throughput possible with an entry-level PIC. > > Thanks, > Nathan > -- Les Troyer Sr. Analyst Siemens Power Corp 2101 Horn Rapids Rd. Richland, Wa. 99352-0130 Voice (509) 375-8695 Fax (509) 375-8940 Operator (509) 375-8100 email .....ljtKILLspam@spam@nfuel.com Ad Hoc, Ad Loc, Quid Pro Quo; So Little Time SO Much To Know. -Jeromy Hillery Dillery Boo, PHD, MS and Q

At 01:16 PM 1/1/97 -0700, you wrote: >Hello all, > >Has anyone looked into using the iButton cans (http://www.ibutton.com) from Dallas >Semi? They use a 1-wire interface which probably would work with a PIC, >though there may be some issues dealing with the 115kbit/sec transfer rate. >These things seem like a great application of the PIC, which could provide >a gateway to real-world elements using the DS1990 as an authentication >tool. Am I totally wrong here? Sorry, I've been lurking in this group for a >while, and haven't made the leap from Stamps to PICs, so I'm not really >familiar with the throughput possible with an entry-level PIC. > >Thanks, > Nathan Nathan, As plenty of other people on the list have stated, hooking a DS1990 to a pic really is not all that hard to do. I did a digital 'lock' using a 16c54 that worked just fine. I would however like to see some of the dallas/pic crc routines because I just faked it. As for the 115kbit/sec specification, that's a bit misleading. The basic time slot period can be anything from 60us to 120us. I believe the 115kbit transfer rate comes from the Dalles Semiconductor software/hardware trick of using the IBM serial port to generate the 1-wire protocol. hope this helps.... carl