• TI Thinks Resolved

CDCE6214-Q1: Questions about circuit design

Prodigy 60 points

Replies: 1

Views: 24

Part Number: CDCE6214-Q1

(1) I want to use a single-ended crystal oscillator for Reference CLK. Is the following port connection correct?
・Connect the CMOS output single-end crystal oscillator (25MHz) to the "PRIREF_P" terminal (5pin).
・"PRIREF_N" terminal (6pin), "SECREF_P" terminal (1pin), "SECREF_N" terminal (2pin) are open
・Pull up the "REFSEL" terminal (4pin) to 3.3V

(2) I2C control cannot be used on my system. Is 100MHz (PCIe Ref-CLK) output just by applying power to CDCE6214?

(3) I want to use CDCE6214 in "Pin Mode". However, I don't know how to set it to "Pin Mode". What should i do?

  • Hello user4384716,

    1. PRIREF_N should be connected to GND, per the pin functions table in the datasheet. Otherwise, correct.
    2. Yes, the default settings for the device expect 25MHz input, 100MHz output. In theory, no register programming is required for the case you describe.
    3. Before final installation of CDCE6214, you must program the EEPROM using direct access method to set the MODE bit (R0[0]) to 1. Once the MODE bit is set to 1 in EEPROM, the device will always start in Pin Mode without requiring any I2C commands.

    Datasheet 10.5.2 discusses EEPROM programming, including a mapping of device registers to EEPROM. Device registers are listed in a separate document. TICS Pro programming software (TICSPRO-SW) can be used alongside a device EVM to test EEPROM configurations and analyze the EEPROM programming sequence.

    Regards,

    Derek Payne

    Texas Instruments