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VCNTL interface

Lars Petter Eliassen
Prodigy 80 points
Other Parts Discussed in Thread: UCD9222

Hi

We are using a C6657CZH device.  The core voltage is controlled by a UCD9222.

Control of the core voltage seems not to work.  After PowerUp I see a low pulse on VCNTL3 (1.7ms long), after this all the VCNTL pins are stable high.

Is this the right behaviour? Is the VCNTL values presented only once after PU?  If so, what is the timing related to RESET?

Otherwise, the chip is functioning OK, with core=1.1V

 

BR

Lars P

 

  • 0
    TI__Mastermind 42545 points

    Hi Lars,

    The C6657 is configured for SmartReflex class 0. As you noted it will only set the voltage once after reset has been released. If you are seeing the VCNTL3 toggle once but the VCNTL2:0 remain high then the part is commanding the power supply to remain at 1.1V.  Some, but not all, C6657s will command 1.1V as an operating point. The timing for the VCNTL interface can be found in the data manual. 

    Regards, Bill