Why 74192 is giving odd counting(explanation)?
in reference of Marianna's ans: it is giving odd counting means 1,3,5,etc i have generated pulse using 555 but it is not directly attached to it rather a 7490 ic triggs 74192. but it gives odd stages.Ic is connected in normal condition with master reset gnd. is there any disturbance created by master reset(MR) because we have previously ORed a signal and gnd and give it MR and then it also shows odd counting.some more thing i want to know that i did try on proteus (computer software) it works correctly. in software counting starts from 0 using 7490 which is also a counter.but in actual counting starts from unknown state. can there be a way of starting counting form 0. if you (Marianna) can't ans then tell me someone id who can ans. thanks
Answer:
"in software counting starts from 0 using 7490 which is also a counter.but in actual counting starts from unknown state."
Most actual IC's you have to reset them to get into a known configuration before you start using them. An easy way of doing this is using a power conditioner IC thats sends out a signal a set amount of time (usually 1ms to 100ms) after power is turned on. Tie this signal to reset so that the chip is reset and in a known state after every power up.
reset your counters with clean pulses.
make sure power is clean. use bypass caps at every chip.
make sure grounds are good.
MIKE
In order to start the 7490 from a 0 count (all outputs low), it is necessary to first set the Reset lines correctly before counting. There are several ways this can be done using the reset lines, but the method as follows would be as easy as any:
R0-1 (pin 2) HIGH (tie this to +5)
R0-2 (pin 3) HIGH (this one needs to change after reset)
R9-1 (pin 6) LOW (tie this to ground)
Once the reset is complete, change R0-2 to LOW.
You will need to create a condition where R0-2 is held high during and shortly after power up, but is soon allowed to drop low after the reset is complete. There are a number of ways to accomplish this in both analog and digital ways. One is to add a pull-up to your R0-2 line and have something in your circuit (like a 555) time out after 100 milliseconds or so and sink the pull-up to drive R0-2 low. Lots of imagination possible there.
.
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Answer:
"in software counting starts from 0 using 7490 which is also a counter.but in actual counting starts from unknown state."
Most actual IC's you have to reset them to get into a known configuration before you start using them. An easy way of doing this is using a power conditioner IC thats sends out a signal a set amount of time (usually 1ms to 100ms) after power is turned on. Tie this signal to reset so that the chip is reset and in a known state after every power up.
reset your counters with clean pulses.
make sure power is clean. use bypass caps at every chip.
make sure grounds are good.
MIKE
In order to start the 7490 from a 0 count (all outputs low), it is necessary to first set the Reset lines correctly before counting. There are several ways this can be done using the reset lines, but the method as follows would be as easy as any:
R0-1 (pin 2) HIGH (tie this to +5)
R0-2 (pin 3) HIGH (this one needs to change after reset)
R9-1 (pin 6) LOW (tie this to ground)
Once the reset is complete, change R0-2 to LOW.
You will need to create a condition where R0-2 is held high during and shortly after power up, but is soon allowed to drop low after the reset is complete. There are a number of ways to accomplish this in both analog and digital ways. One is to add a pull-up to your R0-2 line and have something in your circuit (like a 555) time out after 100 milliseconds or so and sink the pull-up to drive R0-2 low. Lots of imagination possible there.
.
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