IP2022 User’s Manual—System Architecture www.ubicom.com 59 Figure  2-14  shows  the  connections  for  attaching  an  external
crystal to the OSC or RTCLK oscillator. For the OSC oscillator, a
crystal between 1 MHz and 6 MHz is connected across the OSC1
and OSC2 pins. For the RTCLK oscillator, a 32.768 kHz crystal is
connected  across  the  RTCLK1  and  RTCLK2  pins.  No  external
capacitors are required. For proper operation of the crystal or resonator, the total printed
circuit board trace length for the OSC1 and OSC2 signals must be
kept to less than 1 inch (2.5 cm) each, and the capacitive loading
must be kept to less than 3 picofarads. Routing should be direct
and no vias should be used. Figure 2-14  Crystal Connection 515-025.eps Crystal Crystal IP2022 OSC1 OSC2 XTAL RTCLK1 RTCLK2 RTCLK