8 bit binary of ADC0804 to decimal view in & segment.

[ikelectro]

then plz tell me what frequency should I give them both for clock and frequency??

 

[ikelectro]

CE = pin 2
DE = pin 3
EO = pin 4 (unused)
2C = pin 14 (unused)



At 9 KHz it will take about 28 ms for the BCD display to count to the final value (do the bin-to-BCD conversion). That's pretty quick as far as the human eye can notice.

i'm giving clock 260hrz then what should i give to convert??plz tell me...

 

[ccurtis]

i'm giving clock 260hrz then what should i give to convert??plz tell me...

1 Hz.

 

[ikelectro]

but here it is a problem. binary 8 bit maximum is 11111111(desimal 255) ,but it sometimes goes above 255.. now its 522 displaying.!!!!!!!!!!!!!1

 

[ccurtis]

Hmmm, that's not the way it is supposed to work. Make sure your clock has clean, fast edges at the proper voltage levels, 0 to +V.

 

[ikelectro]

Hmmm, that's not the way it is supposed to work. Make sure your clock has clean, fast edges at the proper voltage levels, 0 to +V.

im using 0V and +5V.whar do you mean by clean clock?

 

[ccurtis]

im using 0V and +5V.whar do you mean by clean clock?

Meaning that the edges don't have significant noise on them. Of course, too, I have to assume that you are using a good power supply and good grounding techniques like connecting all grounds to a single point. I've double-checked the design and didn't find any issues. Have you built clocked digital circuits before?

 

[ikelectro]

Meaning that the edges don't have significant noise on them. Of course, too, I have to assume that you are using a good power supply and good grounding techniques like connecting all grounds to a single point. I've double-checked the design and didn't find any issues. Have you built clocked digital circuits before?

at last it works nicely. Thank you you very much for your help.
i just uploaded a video see this plz...about this circuits.

 

[ccurtis]

That's very cool. Good job. Thank you for sharing that! If you can make the duty cycle of the convert clock smaller so that is high for only a very small fraction of the time it is low, the display will not show all zeros for so long, and it will look more like a series of readings from the ADC only.

 

[ikelectro]

That's very cool. Good job. Thank you for sharing that! If you can make the duty cycle of the convert clock smaller so that is high for only a very small fraction of the time it is low, the display will not show all zeros for so long, and it will look more like a series of readings from the ADC only.

yes. yes. i can do... But i can tell you that if you dnt help me i cant come to this.. thnanks once again.

 

[ikelectro]

can you explain me the working principle of this circuit??

 

[crutschow]

can you explain me the working principle of this circuit??

It's fairly simple. You load the binary number into the binary counter and then count down to zero. At the same time you count the BCD counter up from zero with the same clock. Since the number of clock pulses to do this is number you are trying to convert, the BCD counter will contain that number at the end. You then display this BCD number.

 

[ikelectro]

Plz can you explain it with the correspond of the circuit..

 

[ccurtis]

A found an error in the design. Certain counts on the BCD counter/display side, such as 10 and 100 may not display correctly because the CE inputs on the 10's and 100's counter/decoder will disable clocking of those devices before the CO output of the proceeding stage gets to clock them, due to internal delay of the CO output. The fix is to just ground the CE inputs of the 10's and 100's counters, as those inputs don't need to be used anyway. See correction attached.

A correction to the original, BCD output only design, for similar reasoning is also attached.

 

[ikelectro]

A found an error in the design. Certain counts on the BCD counter/display side, such as 10 and 100 may not display correctly because the CE inputs on the 10's and 100's counter/decoder will disable clocking of those devices before the CO output of the proceeding stage gets to clock them, due to internal delay of the CO output. The fix is to just ground the CE inputs of the 10's and 100's counters, as those inputs don't need to be used anyway. See correction attached.

A correction to the original, BCD output only design, for similar reasoning is also attached.

oki. ok. i make this out..

 

[harsh_agr]

Can we use the above interfacing for adc0808?

 

[ikelectro]

Can we use the above interfacing for adc0808?

that'll be same, you have to just give the out put of 8080 to the input of the counter.

 

[harsh_agr]

I am making a digital thermometer where I'll b using LM 35 and it's o/p is fed to ADC0808 after which I'll b using the above logic for 8-bit binary to BCD conversion.....however I tried implementing the ckt on Multisim using 4026 and 4510 and manually providing an input to the 4026 ic's....
Cud u tell me what clock and converter frequency would I require for this particular application? I tried using 1Hz (converter) & 2560 Hz (clock) but the o/p was improper...the BCD counter kept on counting upto 99 in an infinite loop and I wasn't getting a fixed answer.

 

[ccurtis]

Cud u tell me what clock and converter frequency would I require for this particular application? I tried using 1Hz (converter) & 2560 Hz (clock) but the o/p was improper...the BCD counter kept on counting upto 99 in an infinite loop and I wasn't getting a fixed answer.

Probe the CE input of U3 to see if it ever goes high to disable the counting of the 4026's when the conversion is complete. If it does not go high, check the wiring of the 4526's. The clock and converter frequency you tried is okay.

Attached is a timing diagram showing the conversion of the binary input of 18h.

 

[harsh_agr]

View attachment 67422