Hi, I need to calculate how much will and application last until its shut off. The application will use a PIC16F913 with NanoWatt technology. It's a very simple circuit, 4 seven segment displays, and nothing more really, it's basically a timer, so it has a clock which I have to maintain in case the device is unplugged from the wall. I run some calculation based on the datasheet, but I would like to check. The devices consumes: - 16.33 uA Normal Operation intosc 4Mhz (averaged with the 2, 3 and 5 volt values) - .45 uA Basic Sleep Mode - 2.66 uA For timer 1 oscillator (32.768 kHz) Now, since the Timer 1 will always be on, I have 2 currents: - 18.99 uA - 3.11 uA The second current will be consumed for the time it takes to the timer 1 to overflow (1 second), the second current will be consumed on power up, and until the device is on sleep mode again, which I estimated to be 1.1 mS. Then, I calculated the average current to be 3.13 uA and using the formula Q = C*V * e^(-t/RC) calculated the time (to reach 2.2V in the cap) to be near 25 hours... Ohh... I use a supercap of 0.1F x 5.5V. I will connect it like this: VCC ---------DIODE-------------PIC | CAP | GND Any opinions? Regards, Mauricio Jancic Janso Desarrollos - Microchip Consultants Program Member info@janso.com.ar www.janso.com.ar (54) 11 - 4542 - 3519 -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Ed Edmondson Sent: Thursday, October 20, 2005 3:02 PM To: Microcontroller discussion list - Public. Subject: Re: [PIC] Question?? Thanks Guys Ed > PORTB<7:4> means port b bits 7 through 4 inclusive (not bits 0 through 3). > > Harold > > On Thu, October 20, 2005 10:39 am, Ed Edmondson wrote: >> I was reading a PIC data sheet and ran across the following statement: >> >> PORTB<7:4> Interrupt on change. >> >> What does the 7:4 indicate?? >> >> Thanks, >> Ed > > > -- > FCC Rules Updated Daily at > http://www.hallikainen.com > -- > http://www.piclist.com PIC/SX FAQ & list archive View/change your > membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist