TMS320VC5409 Fixed-Point Digital Signal ... - Texas Instruments

Documentation Support5.4 Internal Oscillator with External CrystalThe internal oscillator is enabled by connecting a crystal across X1 and X2/CLKIN. The frequency of CLKOUTis a multiple of the oscillator frequency. The multiply ratio is determined by the bit settings in the CLKMDregister. The crystal should be in fundamental-mode operation, and parallel resonant, with an effective seriesresistance of 30 Ω and power dissipation of 1 mW.The connection of the required circuit, consisting of the crystal and two load capacitors, is shown in Figure 5−2.The load capacitors, C 1 and C 2 , should be chosen such that the equation below is satisfied. C L in the equationis the load specified for the crystal.C L C 1C 2(C 1 C 2 )Table 5−1. Recommended Operating Conditions of Internal Oscillator With External CrystalMIN MAX UNITfclock Input clock frequency 10 20 MHzX1X2/CLKINCrystalC1C2Figure 5−2. Internal Oscillator With External Crystal52 SPRS082FApril 1999 − Revised October 2008