Main Clock Control A

Name:
MCLKCTRLA
Offset:
0x00
Reset:
0x00
Access:
Configuration Change Protection
Bit76543210
CLKOUTCLKSEL[3:0]
AccessR/WR/WR/WR/WR/W
Reset00000

Bit 7 – CLKOUT: Main Clock Out

Main Clock Out

This bit controls whether the main clock is available on the Main Clock Out (CLKOUT) pin or not when the main clock is running.

This bit is cleared when a ‘0’ is written to it or when a Clock Failure Detection (CFD) condition with the main clock as the source occurs.

This bit is set when a ‘1’ is written to it.

ValueDescription
0 The main clock is not available on the CLKOUT pin
1 The main clock is available on the CLKOUT pin

Bits 3:0 – CLKSEL[3:0]: Clock Select

Clock Select

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

ValueNameDescription
0x0 OSCHF Internal high-frequency oscillator
0x1 OSC32K 32.768 kHz internal oscillator
0x2 XOSC32K 32.768 kHz external crystal oscillator
0x3 EXTCLK External clock or external crystal, depending on the SELHF bit in XOSCHFCTRLA
Other Reserved Reserved