10.5.1 Main Clock Control A

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. The CLKOUT pin is available for devices with 20 pins or more. See section I/O Multiplexing and Considerations for more information.

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).

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