CDCE6214: Clock problem

Hi Danilo,

I was able to replicate this error on my end as well, it looks like this is a bug with how TICS Pro calculates the frequency plan given an output that has infinite decimal places. If you mouse over the frequency, it will display a tooltip that tells you the exact frequency as a fraction (see below).

This should only affect this specific feature of TICS Pro, and the CDCE6214 should be able to output this frequency just fine with these settings.

Best,

Jaryd

Hi Jaryd,

Thank you for your reply. I'm the customer in the original question. So from your message that the CDCE6214 will output 128/7MHz frequency according to the configured parameters. So my further question is that how to can get the right CDCE6214 loop filter parameters for my design. It looks like that the loop filter data never change according to any frequency whatever I set... (the loop filter data showing on tics pro never change) Is there any solution to this? Thank you and I'm looking forward to hearing from you.

Best,

Ken

Hi Ken,

The loop filter parameters do not set the output frequency, so you shouldn't see any changes in the loop filter when you adjust the output frequency. Changing the output frequency should only affect the dividers and VCO frequency.

The loop filter will affect different parts of the PLL design, such as the loop bandwidth, lock time, and overall phase noise. TI has a tool called PLLatinum Sim that can help you with your loop filter design. We unfortunately do not have a specific CDCE6214 device to configure, but using a custom device should give you an idea of how to configure the loop filter to achieve your desired loop bandwidth characteristics.

Best,

Jaryd

Hi Jaryd,

Thank you for your reply. Continue with the previous question, I'm wondering what is the sequence of configuration from register R0-R85? Could you please tell me where to find any guideline document to complete all the writes and reads through I2C interfere? Is there such guideline document to help? Thank you and I'm looking forward to hearing from you.

Best,

Ken

Hi Ken,

Information on the register mapping of the CDCE6214 can be found in the register map user guide. Details on how to interface the device with I2C can be found in the datasheet as well. 

Best,

Jaryd

Hi Jaryd,

Sorry I have another related question: There are 86 registers in CDCE6214, what sequence should I take to program all these registers through I2C interfere with a mcu? Thank you! 

Best,

Ken

Hi Ken,

The specific setup of interfacing the CDCE6214 and an MCU depends on which MCU you're using. We have a short tech document about interfacing I2C with TI's MSPs here --> MSP MCU I2C Getting Started Guide (this is only if you're using an MSP MCU).

Some general I2C considerations are:

• The CDCE6214 should be operating in serial interface mode.
• There should be pull-up resistors on the SDA and SCL lines to VDD_REF, the specific value of which should be listed in the MCU's datasheet. Traditionally this value is 4.7kΩ.

Info on the typical application and implementation of the CDCE6214 with I2C can be found in section 8 of the datasheet as well.

Best,

Jaryd