G'day Chaps
I am having a few problems with the use of a 4040 as a divide by 512 on a 4046 PLL.
The wretched thing is giving me a frequency of 256 x clock instead of 512 x clock using pin 12 (Q8).
I would be grateful of a bit of an explanation here. Wondered if it's due to the ripple counter glitches?
I realise these are neanderthal nowadays but the project requires nothing 'state-of-the-art' really.

Regards
Nick

 

using pin 12 (Q8).

Q8 is pin 13, Q9 is pin 12.

 

Hmmm, just checked on my schematic 'Diptrace'. HEF4040 pin 12=Q8......... pin 14 = Q9 (datasheet agrees. (P9 =Q0)

 

The individual outputs of a ripple counter do not have glitches. Ripple counter glitches appear only when multiple outputs are being combined in gate logic, like AND-ing two or more outputs together to decode a non-binary-increment value. The glitch comes from the time delays among the transitions of the individual stages.

ak

 

Hmmm, just checked on my schematic 'Diptrace'. HEF4040 pin 12=Q8......... pin 14 = Q9 (datasheet agrees. (P9 =Q0)

What datasheet are you looking at? This datasheet says that Q9 (14) is the divide by 512 output. Q8 (12) is divide by 256.

 

Over the years there has been some variation in the 4020, 4024, 4040, and 4060 datasheets and in CAD libraries about what to call the outputs. If the output of the first flipflop is Q0, then how do you designate the output of the 4060's oscillator, Q-1? That is why it *always* is a good idea to check the internal schematic or block diagram to see how the output stages relate to the input signal.

ak

 

Hmmm....
Title says 'CD4040', TS reply says 'HEF4040' and apparently the pinouts are different.

 

Or rather the names of the pins are different.
CD - Q1 to Q12
HEF - Q0 to Q11

 

So whichever chip you have, pin 14 is the divide-by-512 output.

 

I have seen Q numbers messed up on CMOS counter chips... for the 4060 I've seen the same chip from different folks count the Q's differently. The example above... one starts on Q1 the other starts on Q0... I like the Q1 number better Either way it should be the same result.

 

Thank you very much gentlemen, my stupid mistake, going backwards and forwards between layouts my ancient eyes got crossed somewhere.
I assumed it would be something daft, or somebody daft (me)............ Q0.....Q1 tomato....tomato

All the best for Easter
Nick

 

Hey don’t put down CMOS chips I love em. Not everything requires programming and flashing.

 

I luv 'em too really. (and valves.....long live the kt88)
What i did here was take out a 4024 and go to a 4040, the 4024 was fine at x128 which is 2\7.
Changed to 4040 ===== wrong! Just glanced at a data sheet, didn't really look. Thought
the 4040 was 2\12 (4096) on Q11 which makes Q8=512.