27c256 | 4K81H | 68HC11A1 | 68HC11P1 | 68hc24 | 68HC711E9 | 68HC811 | 8255 | A2D | ADC | ADC12138 | Am85C30 | BRCLR | Buffalo | CMOS | EEPROM | EPROM | Ethernet | EVB | EVBU | HC11E1 | HC11E9 | HC711E9 | Horray | ImageCraft | IRQ | Keypad | LCD | MC68HC11D0FN | MC68HC11E1CFU3 | MC68HC11F1 | MC68HC711E9 | MC68HC711E9CFN2 | Microcore11 | Microstamp11 | Minikit | NVRAM | PSD | PSD8xx | PSD9xx | PT1000 | RS232 | RTS | RXD | SPI | SRAM | TXD | Watchdogs | XIRQ

Musibau: Another item to look for is uninitialized interrupt vectors. I have seen noise trigger an IRQ or XIRQ, even with pullups. Make sure that all unused interrupt vectors point to the start of your code, or to an actual ISR with nothing in it but an RTI instruction. > Thanks a million Chris, noise is one of my suspicion but as you > well know this is though to prove. I suspect noise because like I > said in my original e-mail this happens about 1% of the time. > > For your information, I do have a 220uf capacitor on the output > of the 5V regulator output and it's about 6inches away from the > HC11. Also just as you did, I only have 0.1uf each and a single > 1uf capacitor on the 5V pins of the HC11. > > Question: It looks to me like I need to change the 1uf to > something higher like the 22uf that you used. Sounds right? > > Thanks > > Darrell Norquay Datalog Technology Inc. Voice: (403) 243-2220 Fax: (403) 243-2872 Email: Web: www.datalog.ab.ca

(You need to be a member of m68hc11 -- send a blank email to m68hc11-subscribe@yahoogroups.com )