Post by thread:RTC (not directly PIC related)

Antonio Almeida wrote: > > Can someone tell me about a RTC to use in a data logger, i need one small > as possible and with built in battery ? > > Thanks. I have data, and working code for Dallas DS-1202/1302 and Panasonic NJU-6355 RTC posted at: http://www.dontronics.com/rtc.html These are all 8 pin devices. I doubt if you will get anything with a battery built in. Perhaps I mis-read the question. Don McKenzie spam_OUTdonTakeThisOuTdontronics.com http://www.dontronics.com PICSTART and Newfound PIC Programmers Firmware Upgrades. SLI, the serial LCD that auto detects baud rates from 100 to 125K bps. SimmStick(tm) A PIC proto PCB the size of a 30 pin Simm Memory Module. Send a blank message to .....helpKILLspam@spam@dontronics.com for more info.

At 06:57 PM 5/13/97 +0000, you wrote: >Can someone tell me about a RTC to use in a data logger, i need one small >as possible and with built in battery ? > >Thanks. > check out dallas semiconductor http://www.dalsemi.com they have small one wire interface but add your own battery or byte wide ram with memory mapped clocks. michael

Hi Antonio >Can someone tell me about a RTC to use in a data logger, i need one small >as possible and with built in battery ? > >Thanks. Think that the most compact RTC in the market with built in battery is Dallas DS-1994. You get RTC, xtal, battery and 512 byte BBRAM all in a stainless steel case of 16mm diameter by 5mm thick. Looks like a big coint cell battery. Any other RTC will need (at least) external battery or, if including battery, it will be a 24 pin DIP block 6mm high. But there are some warnings on using this device: 1) Clock is just a 5 byte binary counter incrementing at 256 times per second. You have to write code to calculate year/month/day/hour/minute/second from that mess. 2) The device is interfaced using the Dallas 1wire protocol. You will have to write code to manage the protocol. The good news is that it'll only get one I/O pin from your CPU. 3) There is no "RTC only" version and if you don't need the 512 bytes of BBRAM you will have to pay for them anyway. But if that is enought for your data logger you can build the whole thing with the DS-1994 and a PIC. Cost in Spain for 100pcs is about $10 each. May be you can find someone who share the PIC code for this. Good luck !. Luis Fernandez Cormenzana RadioBit Sistemas, S.L. Vehicle fleet control systems Patrol presence controllers Fax/Tel:+34-6-585 64 57 e-mail: radiobitKILLspamdragonet.es http://www.dragonet.es/users/radiobit