Hi, in this post we will do a review of our clock project with the MSP430-F2013, before leaving for the layout. As you can see in electronics projects are made and remade, until they reach the required capacity, so we will have multiple versions of Alpha, Beta ...
Let's start by reviewing the problem of consumption, first observe that the largest expense lcd backlight came from, so we should turn it and only connect when it is pressed a button to check the time. For this we will use a 555 to function as timer and turn off the led lcd, this because the micro ports are crowded, so cannot resolve the problem in hardware, software only on its mounting was configured as the datasheet. Second, another expense that will be cut off is of LM7805, so rather than use a 9V battery will use a 5V which has generally 2000mAh. Now in this way we will have increased to lifetime of approximately 7 months clock.
Other changes required for the project is the addition of resistors in the communication of lcd and HT1380 to the MSP. This increase is necessary due to the potential difference between the micro and the components are 5V in the instant communication, there is some barrier to current is extremely high, so there must be binding on resistors. An appropriate value for the resistors for the lcd 47 kΩ is and for the HT is 1 k ohms.
For connection to LM35 will do a filter "pi" is a low pass filter to eliminate multiple frequency oscillator, with two capacitors and one inductor as noted in this second version of the schematic.
Now our schematic is ready and we can go to the layout in the next post.