i'm making a simple 7-segmented digital clock using 7493 (4 bit binary counters) for my room...
the design is simple.. but i'm facing problem in the 'hour' logic... i want it to reset at 24 hrs...
at the 'hour' part the 1st 7493 counts from 0-9 (10th being the reset condition fed to an AND gate)
the 2nd 7493 counts from 0-2(3 being the reset condition, fed to another AND gate)
now wht i did was that i AND the logic output 4(0100) of 1st 7493 with logic o/p 3(0011) of 2nd 7493 and fed its o/p to an OR gate with the 1st's i/p of logic 10(1010)... i hope u are getting it.
i have checked the OR gates, AND gates... they are all in working condition but still i'm not getting the desired output... some how the hour part goes up to 30 (0-29)... i can't have 29 hrs a day!!
can someone tell me how to implement 24hrs (0-23) on the hour segments..
lastly i have thought of adding 2 time set button..simple push button switch does the trick. one end of the button is +ve volts and second is the clock input of 7493.. when i press it, a sort of extra pulse gets in and counts up the part its connected to... so i placed push button switch one at the minute part (the 3rd 7493 from right) and 2nd button at the hour part (5th 7493 from right)... oh yes, i have to place diodes in place of wires that are carrying the clock pulses to 7493s, other wise when i try to set time the positive supply's momentary pulse from push button destroys the AND gate (after several times of pushing)
the design is simple.. but i'm facing problem in the 'hour' logic... i want it to reset at 24 hrs...
at the 'hour' part the 1st 7493 counts from 0-9 (10th being the reset condition fed to an AND gate)
the 2nd 7493 counts from 0-2(3 being the reset condition, fed to another AND gate)
now wht i did was that i AND the logic output 4(0100) of 1st 7493 with logic o/p 3(0011) of 2nd 7493 and fed its o/p to an OR gate with the 1st's i/p of logic 10(1010)... i hope u are getting it.
i have checked the OR gates, AND gates... they are all in working condition but still i'm not getting the desired output... some how the hour part goes up to 30 (0-29)... i can't have 29 hrs a day!!
can someone tell me how to implement 24hrs (0-23) on the hour segments..
lastly i have thought of adding 2 time set button..simple push button switch does the trick. one end of the button is +ve volts and second is the clock input of 7493.. when i press it, a sort of extra pulse gets in and counts up the part its connected to... so i placed push button switch one at the minute part (the 3rd 7493 from right) and 2nd button at the hour part (5th 7493 from right)... oh yes, i have to place diodes in place of wires that are carrying the clock pulses to 7493s, other wise when i try to set time the positive supply's momentary pulse from push button destroys the AND gate (after several times of pushing)