[SOLVED] Hz vs number of bits

My question is very elementary, yet tricky.

Say for example: I have a digital clock of 10MHz. I need to trigger an operation at 10ms.

So how many bits I will be needing, after counting which I will be at 10ms? (Number of bits in counter).

Please elaborate a little.

Thanks in advance.

- - - Updated - - -

Ok got answer. Sharing it for general info here.

For 10MHz, the time period for one cycle is 0.00000001 second. For counting a time of 10ms, we will divide 10m by .00000001. This will give us a count of 100000. So, we will count 100000 with a clock, that has a single cycle of .00000001 seconds in order to reach 10ms timings. So in order to count 100000 we need 17 bits(*11000011010100000‬).

Thanks anyway

Glad you enjoyed having a conversation with yourself, but there’s an easier way:

10E-3*10E6=100E3

Log(100E3) /log(2)=>17

barry said:

Glad you enjoyed having a conversation with yourself, but there’s an easier way:

10E-3*10E6=100E3

Log(100E3) /log(2)=>17

Click to expand...

My method is indeed difficult, but explains everything.

barry said:

Glad you enjoyed having a conversation with yourself, but there’s an easier way:

10E-3*10E6=100E3

Log(100E3) /log(2)=>17

Click to expand...

don't you need just 16 bits? since you only need to count to 100E3/2, toggle clk, count 100E3/2 again and toggle?

Hi,

don't you need just 16 bits? since you only need to count to 100E3/2, toggle clk, count 100E3/2 again and toggle?

Click to expand...

Correct. For the counting.
But you need an extra bit (flip flop) for the "toggle".

Klaus

KlausST said:

Hi,


Correct. For the counting.
But you need an extra bit (flip flop) for the "toggle".

Klaus

Click to expand...

Isn't it possible to add combi logic to represent a toggle enable?

Hi,

Yes, for "toggle enable"....but this is just a signal as input to the toggle flipflop.

Klaus