The Crystal OSC block provides an amplifier circuit which can generate a highly precise and stable digital clock signal (OUT) from a quartz crystal or ceramic resonator. When activated, the inverter amplifier is connected to PIN16 (output) and PIN17 (input). Proper feedback resistance and capacitance must be applied for the oscillation circuit to function. Please refer to the table below for recommended external component values.

Table 1. External Components Selection Table
Frequency (MHz) C1, C2 Feedback Resistor
5 33 pF 5 kOhms
10 22 pF 1 kOhms
15 15 pF 500 Ohms
20 10 pF 270 Ohms

Activation


Set the parameter ‘Enable crystal oscillator’ to Enable.

Parameters


Enable crystal oscillator:

Enable: block is enabled and connected to PIN16 (output) and PIN17 (input).

Disable: block is shut off. PIN16 and PIN17 no longer used by this block.


Power down enable:

A Power Down PIN that controls both the Temp Sensor and Crystal OSC. 1 = Power UP and 0 = Power DOWN. To fully enable a block, the components must first be activated. See ‘Activation’.

No matrix PD:PD input disabled. Crystal OSC and Temp Sensor are always on.

PD for crystal OSC: Control crystal OSC’s on/off state. Temp Sensor is always on.

PD for TEMP SENSOR: Control Temp Sensor’s on/off state. Crystal OSC is always on.

PD for crystal OSC & TEMP SENSOR: Control both crystal OSC’s and Temp Sensor’s on/off state with this signal.