32.22.8 PMC Clock Generator Main Oscillator Register

This register can only be written if the WPEN bit is cleared in the PMC Write Protection Mode Register.
Name: CKGR_MOR
Offset: 0x0020
Reset: 0x01000021
Property: Read/Write

Bit 3130292827262524 
      XT32KFMECFDENMOSCSEL 
Access R/WR/WR/W 
Reset 001 
Bit 2322212019181716 
 KEY[7:0] 
Access WWWWWWWW 
Reset 00000000 
Bit 15141312111098 
 MOSCXTST[7:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 76543210 
  ZEROONEZEROMOSCRCENWAITMODEMOSCXTBYMOSCXTEN 
Access R/WR/WR/WR/WR/WR/WR/W 
Reset 0100001 

Bit 26 – XT32KFME 32.768 kHz Crystal Oscillator Frequency Monitoring Enable

ValueDescription
0 The 32.768 kHz crystal oscillator frequency monitoring is disabled.
1 The 32.768 kHz crystal oscillator frequency monitoring is enabled.

Bit 25 – CFDEN Clock Failure Detector Enable

ValueDescription
0

The clock failure detector is disabled.

1

The clock failure detector is enabled.

Bit 24 – MOSCSEL Main Clock Oscillator Selection

ValueDescription
0

The 12 MHz RC oscillator is selected.

1

The 8 to 24 MHz crystal oscillator is selected.

Bits 23:16 – KEY[7:0] Password

ValueNameDescription
0x37 PASSWD

Writing any other value in this field aborts the write operation.

Bits 15:8 – MOSCXTST[7:0] 8 to 24 MHz Crystal Oscillator Start-up Time

Specifies the number of Slow clock cycles multiplied by 8 for the crystal oscillator start-up time.

Bit 5 – ONE Must Be Set to 1

Bit 5 must always be set to 1.

Bits 4, 6 – ZERO Must Be Set to 0

Bits 4 and 6 must always be configured to 0.

Bit 3 – MOSCRCEN 12 MHz RC Oscillator Enable

When MOSCRCEN is set, the MOSCRCS flag is set once the RC oscillator start-up time is achieved.

ValueDescription
0

The 12 MHz RC oscillator is disabled.

1

The 12 MHz RC oscillator is enabled.

Bit 2 – WAITMODE ULP1 Mode Command (Write-only)

ValueDescription
0

No effect.

1

Puts the device in ULP1 mode.

Bit 1 – MOSCXTBY 8 to 24 MHz Crystal Oscillator Bypass

When MOSCXTBY is set, the MOSCXTS flag in PMC_SR is automatically set.

Clearing MOSCXTEN and MOSCXTBY bits resets the MOSCXTS flag.

When Main Oscillator Bypass is disabled (MOSCXTBY = 0), the MOSCXTS flag must be read as 0 in PMC_SR prior to enabling the main crystal oscillator (MOSCXTEN = 1).

ValueDescription
0

No effect.

1

The 8 to 24 MHz crystal oscillator is bypassed. MOSCXTEN must be cleared. An external clock must be connected on XIN.

Bit 0 – MOSCXTEN 8 to 24 MHz Crystal Oscillator Enable

A crystal must be connected between XIN and XOUT.

When MOSCXTEN is set, the MOSCXTS flag is set once the crystal oscillator start-up time is achieved.

ValueDescription
0

The 8 to 24 MHz crystal oscillator is disabled.

1

The 8 to 24 MHz crystal oscillator is enabled. MOSCXTBY must be cleared.