10.5.1 Main Clock Control A

Name: MCLKCTRLA
Offset: 0x00
Reset: 0x00
Property: Configuration Change Protection

Bit 76543210 
 CLKOUT     CLKSEL[1:0] 
Access R/WR/WR/W 
Reset 000 

Bit 7 – CLKOUT System Clock Out

When this bit is written to '1', the system clock is output to the CLKOUT pin.

When the device is in a sleep mode, there is no clock output unless a peripheral is using the system clock.

Bits 1:0 – CLKSEL[1:0] Clock Select

This bit field selects the source for the Main Clock (CLK_MAIN).

ValueNameDescription
0x0 OSC20M 16/20 MHz internal oscillator
0x1 OSCULP32K 32.768 kHz internal ultra low-power oscillator
0x2 XOSC32K 32.768 kHz external crystal oscillator
0x3 EXTCLK External clock