>CSTCE8M00G55Z=20 Have you used higher frequency >8MHz? This part is a "CE" type (small cap c= hip=20 type), and it is listed as 33pF on digikey. It is within the cap range PICs= =20 would like (15pF to 3xpF) at 8MHz. I have encounter an Abracon Corporation 24MHz resonator with 15pF built-in = cap,=20 but the PIC I have tested doesn't like it. On the test, 1/3 of the chances,= the=20 resonator simply cannot oscillate (Tested on PIC18Fs and dsPIC30Fs). Funny N. Au Group Electronics, http://www.AuElectronics.com http://www.AuElectronics.com/products http://augroups.blogspot.com/ ________________________________ From: Brent Brown To: Microcontroller discussion list - Public. Sent: Sat, November 27, 2010 12:19:18 AM Subject: Re: [PIC] Ceramic Resonators > >2. Packaged resonators are much smaller than crystals . >=20 > This is quite interesting, I actually thought HC49 SMD takes less space > than Ceramic resonator or they should be very close on PCB real estate. > Am I wrong? >=20 > >3. Cost is less than 1/2 that of crystals, and comes with the two=20 > phase-shift caps built-in. >=20 > Any part number on Mouser or digikey? The HC49 SMD crystal I am using is > around 30 Cents in 1K quantity. Actually some ceramic resonator I have > checked with 0.x% accuracy performance either cost more or cost about > the same. I'm a resonator type person, most recently I've used the Murata CSTCE8M00G55Z in small quantities from Farnell (Element14) and also listed by Digi-Key & Mouser. These ones are a nice small physical size (close to 0805 size but longer), anything bigger looks out of place next a QFN packaged micro. No doubt you can find something cheaper... but for me Murata is a trustworthy name and I've had good experience with their resonators coupled to PIC micros. In this application they are in a high vibration environment (brush chipper/tree shredder) and I haven't had any failures yet, touch wood :-P I did try using the internal RC oscillator once for serial comms between two PIC16F886's. Datasheet spec of 1% (IIRC) seemed good enough, and it almost was. I had devices operating at different temperatures, and some pairs wouldn't talk to each other. I could have persisted and tried auto baud rate detection or other tricks, but in the end I switched to a 3 terminal resonator and the problem just went away. --=20 Brent Brown, Electronic Design Solutions 16 English Street, St Andrews, Hamilton 3200, New Zealand Ph: +64 7 849 0069 Fax: +64 7 849 0071 Cell: +64 27 433 4069 eMail: brent.brown@clear.net.nz --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist =20 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .