S
[email protected]
- Jan 1, 1970
- 0
Hi, I am currently working on an 8-digit counter circuit for counting
the revolutions of a motor. I have constructed a modified version of
the 6-digit BCD counter circuit that can be found on the MC14553B
datasheet.
The problem is that the display will not show the correct information.
It would do one of the following: 1. only one display counts correctly,
usually the LSB or the MSB, 2. two of the displays show the same
numbers, or 3. the displays show random numbers.
I reckon it has something to do with timing in the area where the
MC14553 scans between the displays and shows the correct information on
the correct displays (i.e. external oscillator, transistor switching).
I've tested DS1-3 (pins 1, 2, & 15) and they should be scanning at a
high frequency (oscillating) but they aren't.
Also all of the digits are inverted (segments that should be lit
aren't, and visa versa). But that can be easily fixed.
I've tried everything I could think of, even built a second 3-digit
counter, but I still come up with the same problem. Both circuits are
built on veroboard.
If anyone knows how to solve this problem or has any ideas could you
please reply asap.
Kind Regards,
Rossco.
the revolutions of a motor. I have constructed a modified version of
the 6-digit BCD counter circuit that can be found on the MC14553B
datasheet.
The problem is that the display will not show the correct information.
It would do one of the following: 1. only one display counts correctly,
usually the LSB or the MSB, 2. two of the displays show the same
numbers, or 3. the displays show random numbers.
I reckon it has something to do with timing in the area where the
MC14553 scans between the displays and shows the correct information on
the correct displays (i.e. external oscillator, transistor switching).
I've tested DS1-3 (pins 1, 2, & 15) and they should be scanning at a
high frequency (oscillating) but they aren't.
Also all of the digits are inverted (segments that should be lit
aren't, and visa versa). But that can be easily fixed.
I've tried everything I could think of, even built a second 3-digit
counter, but I still come up with the same problem. Both circuits are
built on veroboard.
If anyone knows how to solve this problem or has any ideas could you
please reply asap.
Kind Regards,
Rossco.