Quote Originally Posted by Bronx68 View Post
Please explain the use of D3 through D7 do make an 'or gate' for reset. Why 100K resistors?
Why not use Q0 from each of the CD4017 counters?
The diodes are used to create a master reset from the PIC and to isolate each 4017's reset from each other. Diodes are usually a lot cheaper than logic for something as simple as this. The 100k is probably on the conservative side as far as a value, unless the designer was trying to reduce race conditions or output glitches by creating a simple RC filter.