MSP430 Based Chronulator (using Launchpad chip)

Step 12 FAQ

Q: What about a case?
A: See my mantel clock case for this project at:
     http://www.instructables.com/id/Mantel-Clock-Case-for-Chronulator-Meter-Clock

Q: How does the code work?
A:  The watchdog is set to delay mode and creates interrupts at 1 second intervals, using ACLK and the 32.768 kHz watch crystal. This allows you to count seconds. Timer_A interrupts are used to generate 2 independent PWM outputs which drive the meters. Port_1 is used to provide interrupts for the minute and hour increment buttons. You will note that there is no loop in the main subroutine. The program is completely interrupt driven after it reaches the end of main(). When not servicing an interrupt the MSP430 is in LPM0.

Q: Why doesn't "spy-by-wire" work?
A:  The most likely cause is that you have a 0.1uF capacitor parallel to the Reset button instead of a 1nF (0.001uF) capacitor.

Q: Can I use a 3.3V voltage regulator instead of a 2.5V one?
A:  Yes, a 3.3V voltage regulator can be used, but you should use 4 AA batteries (6V) instead of 3 (4.5V). The battery count is increased so the batteries can age with out causing PWM calibration problems. The regulator should be LDO and low Iq.

 

Comments

[thelagged]

Awesome clocks!