Path: utzoo!utgpu!watmath!clyde!att!rutgers!deimos!cseg!hcx!gmg From: gmg@hcx.uucp (Greg M. Garner) Newsgroups: sci.electronics Subject: Re: Real time clock chip needed Summary: Use a mostek 48T02 Message-ID: <1395@cseg.uucp> Date: 9 Dec 88 06:27:49 GMT References: <8519@burdvax.PRC.Unisys.COM> Sender: netnews@cseg.uucp Distribution: na Organization: College of Engineering, University of Arkansas, Fayetteville Lines: 23 In article <8519@burdvax.PRC.Unisys.COM>, coltoff@PRC.Unisys.COM (Joel Coltoff) writes: > Does anyone know of a real time clock chip that can interface directly > to an 8051. Everyone I've seen so far is to slow to interface at 16 MHz. > The 8051 can't be wait stated so there aren't many options. I really don't > want to latch the data and extend the WR & RD pulses with one shots. > Any advice would be greatly appreciated. Samples would be nice too. > -- > - Joel > {psuvax1,sdcrdcf}!burdvax!coltoff (UUCP) > coltoff@burdvax.prc.unisys.com (ARPA) How about using the mostek 48T02 real time battery backed static ram? This little beauty has a real time clock in it, with a crystal, and it even has a lithium battery mounted in it! It also has software calibration, software battery fail detection, and almost 2K of battery backed ram. You can get these in 200ns, 150ns, not sure about 100ns. I don't know a lot about the 8051, so I don't know if this is fast enough, but I suspect that it is. These can be gotten from Schweber, or mostek. Good luck! Greg Garner 501-442-4847 USENET: ...!uunet!harris.cis.ksu.edu!hcx!gmg