[time-nuts] Si570 question

Jim Lux jimlux at earthlink.net
Tue Nov 18 12:58:26 EST 2014


On 11/18/14, 8:04 AM, paul swed wrote:
> I just picked up the si5351a and the thing that jumps out at mee is the 228
> registers to program.
> Granted it lets you create just about any frequency and there is a good
> program that tells you what to set the registers to. But 228 registers is a
> lot.
> The traditional I2C is indeed simple. Make sure you watch the LSB order and
> setup times.
> I see there are various ebay class boards to connect to usb for a few $ and
> also boards that let you program in Windows studio as an example.
> Or as you want to do straight out of a micro.

yes, there are a lot of registers, but there is some code out there to 
manage them, which I haven't actually looked at.

The micro I'm using does I2C quite nicely, and I've used it for a 
variety of devices.

I was wondering more about RF aspects.. How much Power supply rejection 
do these things have (yeah, the ap note shows a single bypass cap, but 
that may be "good enough to demonstrate function")... and how much 
harmonic output content is there.




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