SPRUI33H November 2015 – June 2024 TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1
The DCC module can be programmed to count down one time by enabling the single-shot mode. In this mode, the DCC stops operating when the down counter0 and the valid counter0 reach 0.
At the end of one sequence of counting down in this single-shot mode, the DCC gets disabled automatically, which prevents further counting. This mode is typically used for spot-checking the frequency of a signal.
Example-1: Validating PLLRAWCLK frequency
A practical example of the usage is to validate the PLL output clock frequency using the XTAL as the reference clock. Assume XTAL is 10MHz, PLL output frequency is 100MHz, SYSCLK is 100MHz, allowable Frequency Tolerance is 0.1%, and DCC Tolerance required is 0.1%. The measurement sequence proceeds as follows:
If there is no error generated at the end of the sequence, then the DONE status flag is set and a DONE interrupt is generated. The application must clear the DONE flag before restarting the DCC.
Error Conditions:
An error condition is generated by any one of the following:
Any error freezes the counters from counting. An application can then read out the counter values to help determine what caused the error.