Programmable Switch Mode Controllers (PSMC) are not just for switching power supplies. This technical brief describes how to use the PIC16C781 PSMC in combination with the Integrated Operational Amplifier, Digital-to-Analog Converter (DAC), and gated timer to construct a thermally operated air flow sensor with minimum external components.
Read more original source:
http://www.microchip.com/stellent/
PIC 16F88 based 4-digit Up-Down counter circuit with explanation
This is a 4 digit decimal counter which can operate as a free running counter or in count and hold mode with manual reset. In either mode the counter can be preset to count to a specified value. Clock edge and leading zero suppression can also be configured. The 7-segment display and indicator LEDs are multiplexed. It will drive most common anode 7 segment LEDs. I used four single digit LEDs but a four digit LED module could also be used. In free running mode the overflow output resets on the next clock pulse. Therefore the pulse duration is directly related to the input clock frequency.
Read Source:http://picprojects.org.uk/projects/counter/counter.htm
