CDCE937: CDCE937P

prabhu k

Part Number: CDCE937
Other Parts Discussed in Thread: CLOCKPRO,

Tool/software:

Hi,

Can you please confirm CDCE937PWR part is preprogrammed ? or how to programmed I2C or resistor setting ?

Please check below schematic for your reference. Can you please suggest how to set required clock outputs (I2C or resistor setting) ?

over 1 year ago

0 prabhu k over 1 year ago

Prodigy 195 points

Can you please suggest how to set required clock outputs (I2C or resistor setting) ?

0 Kadeem Samuel over 1 year ago in reply to prabhu k

TI__Mastermind 23280 points

Prabhu,

The CDCE937 can be programmed using the TI ClockPro programming software (https://www.ti.com/tool/CLOCKPRO) with the programming board (https://www.ti.com/tool/CDCEL9XXPROGEVM).

Setting R6[0] to a '1' initiates the EEPROM write cycle, where the contents of the registers are written to the internal EEPROM. Use ClockPro to determine the register settings to use for programming.
Thanks,
Kadeem

0 prabhu k over 1 year ago in reply to Kadeem Samuel

Prodigy 195 points

Hi Kadeem,

Thank you for your support.

Can you please confirm, Device was pre-programmed already ?

Instead of I2C interface , can I use resistor configuration to generate clock output ?

0 Kadeem Samuel over 1 year ago in reply to prabhu k

TI__Mastermind 23280 points

Prabhu,

The device is preprogrammed for the default settings listed in the datasheet, as is stated in 7.3.2 Default Device Setting:

If the configuration needs to be changed to anything outside of this, it must be done through I2C.

Thanks,

Kadeem

0 prabhu k over 1 year ago in reply to Kadeem Samuel

Prodigy 195 points

Hi Kadeem,

Can I change output clock using resistor configuration instead of I2C interface, please check below schematic, suggest any changes required ?

0 Kadeem Samuel over 1 year ago in reply to prabhu k

TI__Mastermind 23280 points

Prabhu,

You MUST use I2C to configure the device for your frequency plan, as it differs from the datasheet default. Use TI ClockPro for determining the register settings.

Otherwise, I do not see any glaring issues.

Thanks,

Kadeem

0 prabhu k over 1 year ago in reply to Kadeem Samuel

Prodigy 195 points

Hi Kadeem,

Without I2C programmer, Can I use external register settings(pullup & pulldown) to get default clock outputs(ex:24MHz,50Mhz etc)

0 prabhu k over 1 year ago in reply to prabhu k

Prodigy 195 points

And also, kindly confirm factory default settings of all output clocks(Y1 to Y7) ? once power up ?

0 Kadeem Samuel over 1 year ago in reply to prabhu k

TI__Mastermind 23280 points

Prabhu,

You MUST use I2C programming to configure the device as shown in your schematic. As I stated previously, the factory default is for all outputs at the same frequency as the input XTAL.

Thanks,

Kadeem

0 prabhu k over 1 year ago in reply to Kadeem Samuel

Prodigy 195 points

Hi Kadeem,

One of the EVK board(DE0-Nano-SoC) factory default output clock are please check below schematic.

Factory Default Configuration: Is this correct ?
50MHz x2
25MHz x3
24MHz x2

1.PLL IC already preprogrammed above clock output ?

2.In above circuit I2C is not connecting to any master(MCU/MPU), just they gave netnames, but external resistors pulled up to 3.3V. And also default I2C address also given, is this using external pullup resistor ?

4.If I use above reference circuit, Can I expect same clock outputs ?(without programming) use only external pullup resistors ?

0 Kadeem Samuel over 1 year ago in reply to prabhu k

TI__Mastermind 23280 points

Prabhu,

The CDCE937 is NOT preprogrammed for your use case. You will need to write the desired config through I2C, and then program it into the EEPROM.
The external pullup resistor MUST be populated, if not here then on another point on the I2C bus.
You MUST use I2C configuration for programming the CDCE937PWR device to this configuration. I cannot speak for what Terasic is doing for the DE0-Nano-SoC. They may be performing this programming in their factory.

Thanks,

Kadeem

Clock & timing

Clock & timing forum

CDCE937: CDCE937P