11.5.5 Internal High-Frequency Oscillator Control A

Name: OSCHFCTRLA
Offset: 0x08
Reset: 0x0C
Property: Configuration Change Protection

Bit 76543210 
 RUNSTDBY FRQSEL[3:0] AUTOTUNE 
Access R/WR/WR/WR/WR/WR/W 
Reset 000110 

Bit 7 – RUNSTDBY Run Standby

This bit controls whether the internal high-frequency oscillator (OSCHF) is always running or not.

Note:
  1. The requesting peripheral, or the main clock, must take the oscillator start-up time into account.
  2. The oscillator signal is only available if requested and will be available after two OSCHF cycles.
ValueDescription
0The OSCHF oscillator will only run when requested by a peripheral or by the main clock (1)
1The OSCHF oscillator will always run in Active, Idle and Standby sleep modes (2)

Bits 5:2 – FRQSEL[3:0] Frequency Select

This bit field controls the output frequency of the internal high-frequency oscillator (OSCHF).
ValueNameDescription
0x01 MHz1 MHz output
0x12 MHz2 MHz output
0x23 MHz3 MHz output
0x34 MHz4 MHz output (default)
0x4-Reserved
0x58 MHz8 MHz output
0x612 MHz12 MHz output
0x716 MHz16 MHz output
0x820 MHz20 MHz output
0x924 MHz24 MHz output
Other-Reserved

Bit 0 – AUTOTUNE Auto-Tune Enable

This bit controls whether the 32.768 kHz crystal auto-tune functionality of the internal high-frequency oscillator (OSCHF) is enabled or not.

ValueDescription
0The auto-tune functionality of the OSCHF oscillator is disabled
1The auto-tune functionality of the OSCHF oscillator is enabled