SBAS940 December 2018 DAC8742H
All of the devices in the DAC8742H family support a variety of clocking options in order to provide system flexibility and reduce overall current consumption in HART applications. The clocking options include: an internal oscillator (HART mode only), an external crystal oscillator, or an external CMOS clock. The selection of the clocking scheme is controlled by the XEN, CLK_CFG1, and CLK_CFG0 pins as described in the table below.
The internal oscillator takes approximately 50 ms to start oscillating from when it is enabled. During this time period the device is unable to perform modulation or demodulation activities.
|1||0||0||No Output||3.6864MHz CMOS clock connected at XTAL1||HART|
|1||0||1||No Output||1.2288MHz CMOS clock connected at XTAL1|
|1||1||0||No Output||Internal oscillator enabled|
|1||1||1||1.2288MHz Output||Internal oscillator enabled, CLKO enabled|
|0||0||0||No Output||Crystal oscillator enabled|
|0||0||1||3.6864MHz Output||3.6864MHz crystal oscillator, CLKO enabled|
|0||1||0||1.8432MHz Output||3.6864MHz crystal oscillator, CLKO enabled|
|0||1||1||1.2288MHz Output||3.6864MHz crystal oscillator, CLKO enabled|
|1||0||0.5||No Output||4MHz CMOS clock connected at XTAL1||FOUNDATION
|1||1||0.5||No Output||2MHz CMOS clock connected at XTAL1|
|0||0||0.5||No Output||4MHz crystal oscillator|
|0||1||0.5||4MHz Output||4MHz crystal oscillator, CLKO enabled|