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Timer inputs double as
interrupt-request lines - 10/08/98 EDN Design Idea
(Several Design Ideas, scroll to find this one. )
The Intel 80186 is a highly integrated 16-bit µP that is common to embedded applications. This µP's built-in
interrupt controller has four interrupt-related pins that you can configure in various ways to achieve the
maximum of four maskable interrupt-request lines. In applications that require more than four interrupt- request
lines, the only way out is to add an external interrupt controller, such as the 8259A. However, an alternative
approach exists: You can through proper programming make the 80186's two timer-input pins function like normal
edge-triggered interrupt request lines. . . . [by Sk Shenoy, Naval Physical And Oceanographic Laboratory, Kochi,
India]
Timer Light Switch
- Typical circuit representative of those used in most
light switch type digital timers. The timer module is normally a PIC or custom chip, and it syncs to the AC line
so that a trigger pulse can be supplied at the right moment. schematic only. . . . [Circuit by Stepan Novotill]
Timer provides power-off function - 05/22/97 EDN Design Idea This circuit is a simple, timed automatic power-off circuit for
12V-battery-powered systems. . . . [by Kamil Elias, Omnica, Huntington Beach, CA]
Timer Pulse Train
Output - Schematic only, no circuit description. . .
[designer unknown]
Timer Reboots PC's - 06/05/97 EDN Design Idea When you
use a PC to control a process or collect data, it's often desirable to have a watchdog timer reboot the computer
if it runs astray. The circuit in Figure 1 uses a PIC16C84. . . . [by Charles Hamilton, Burr-Brown Corp, Tucson,
AZ]
Timer Remembers Your Rhythm -
01/05/95 EDN Design Idea The unpretentious controller in Fig 1 remembers the interval between your pressing its
start and stop buttons. Thereafter, the controller switches the load on and off every day at the same times as
you did. You reset the controll. . . [by MS Nagaraj, ISRO Satellite Centre, Bangalore, Karnataka, India]
Timer warns when pills are due
- 05/10/01 EDN Design Idea Some people need to take medication at precise, regular intervals. When you're in a
hospital, a medical staff is present to ensure that you take your medication on time. But when you're taking
medication at home, you must frequently look at the clock-a clear annoyance. When my wife was pregnant, she
needed to take medication every two hours from 8 am to 10 pm. To help her time the two-hour intervals, I built
the battery-powered circuit in Figure 1. The circuit derives its power from a 9V PP3 battery. All the ICs are
CMOS-based; the low power consumption of the circuit allows one-week autonomy. When you press the start button,
BP1, a two-hour delay commences. . . . [by J Terrade]
Timer with 555 - Some useful circuits using the LM555 IC. Scroll to find the Timer with 555 circuit. . .
[Jose Pino]
Timer with Alarm Circuit - This simple alarm timer circuit is made with 4060 which has an integrated oscillator with a
good stability with a relatively wide frequency range. In the circuit diagram the oscillator frequency is set by
the RC network that is connected at pins 9, 10 and 11. When the timer with alarm circuit is connected with S1,
the pulse. . . [Circuit posted by Popescu Marian]
Timer with
Musical Alarm - This low-cost timer can be used for
introducing a delay of one minute to two hours. After the timing period is over, a musical song is heard. . . .
[© EFY Enterprises Pvt. Ltd. All rights reserved.]
Timers Collection - Did you know there are at least 6 different kinds of timers? This circuit implements all of
them! With our complete PCB design, you can build yourself an universal module, compelte with power regulator. .
. . [Projects & Ideas from Nutchip.com]
Timers Generate Variable-Sweep Frequencies - 08/01/96 EDN Design Idea The circuit inFigure 1 generates a 4- to 5-kHz output frequency
that precisely sweeps a variable amount of 1 to 100 Hz over a variable time of 0. 5 to 5. 0 sec (1000-to-1 rate
range). The resolution is 1 Hz, and worst-case accuracy during the sweep is 3 Hz (0. 06%). This circuit was
designed to run from an 8-bit PC ISA bus, but any µC with an 8-bit bus and the appropriate control signals can
control the circuit. With a 25-MHz clock source, this circuit can generate a frequency as low as 3. 052 kHz, and
the theoretical maximum is 12. 5 MHz, although frequency sweeping would start after approximately 1. 3 msec. . .
. [by D Hayden, Hayden Electronics Design, San Diego, CA]
Timer's Various Using a 555 - Some Useful Timers, as
Requested by some of my Readers. , including Apply Power, A Time Delay, than Permanent ON till power down. ,
Apply Power = Delay, than On, Delay off, On, Delay off & Repeating. . . . [G.L. Chemelec]
Timing Margin Analysis for Clock
Buffers in High Speed Synchronous Networking Systems - App
Note # 018. . . [Pericom Semiconductor]
Tiny
Timer - Developing a lighting control unit recently, the
author found that available analogue or mechanical timers were not sufficiently accurate or convenient. Without
further ado he developed a timer switch driven by a small AVR controller of the type ATtiny2313must register on
this site. . . [Published in Elecktor July/Augu, 2010]
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