32KHz Internal Oscillator (OSC32K) Control

Name:
OSC32K
Offset:
0x18 [ID-00001010]
Reset:
0x0000 0080 (Writing action by User required)
Access:
PAC Write-Protection
Bit3130292827262524
Access
Reset
Bit2322212019181716
CALIB[6:0]
AccessR/WR/WR/WR/WR/WR/WR/W
Reset0000000
Bit15141312111098
WRTLOCKSTARTUP[2:0]
AccessR/WR/WR/WR/W
Reset0000
Bit76543210
ONDEMANDRUNSTDBYEN1KEN32KENABLE
AccessR/WR/WR/WR/WR/W
Reset10000

Bits 22:16 – CALIB[6:0]: Oscillator Calibration

Oscillator Calibration

These bits control the oscillator calibration. The calibration values must be loaded by the user from the NVM Software Calibration Area.

Bit 12 – WRTLOCK: Write Lock

Write Lock

This bit locks the OSC32K register for future writes, effectively freezing the OSC32K configuration.

ValueDescription
0 The OSC32K configuration is not locked.
1 The OSC32K configuration is locked.

Bits 10:8 – STARTUP[2:0]: Oscillator Start-Up Time

Oscillator Start-Up Time

These bits select start-up time for the oscillator.

The OSCULP32K oscillator is used as input clock to the start-up counter.

Table 1. Start-Up Time for 32KHz Internal Oscillator
STARTUP[2:0] Number of OSC32K clock cycles Approximate Equivalent Time [ms]
0x0 3 0.092
0x1 4 0.122
0x2 6 0.183
0x3 10 0.305
0x4 18 0.549
0x5 34 1.038
0x6 66 2.014
0x7 130 3.967
Note:
  1. 1.Start-up time is given by STARTUP + three OSC32K cycles.
  2. 2.The given time assumes an XTAL frequency of 32.768kHz.

Bit 7 – ONDEMAND: On Demand Control

On Demand Control

This bit controls how the OSC32K behaves when a peripheral clock request is detected. For details, refer to OSC32K Sleep Behavior.

Bit 6 – RUNSTDBY: Run in Standby

Run in Standby

This bit controls how the OSC32K behaves during standby sleep mode. For details, refer to OSC32K Sleep Behavior.

Bit 3 – EN1K: 1KHz Output Enable

1KHz Output Enable

ValueDescription
0 The 1KHz output is disabled.
1 The 1KHz output is enabled.

Bit 2 – EN32K: 32KHz Output Enable

32KHz Output Enable

ValueDescription
0 The 32KHz output is disabled.
1 The 32KHz output is enabled.

Bit 1 – ENABLE: Oscillator Enable

Oscillator Enable

ValueDescription
0 The oscillator is disabled.
1 The oscillator is enabled.