Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Datenbogen
Produktcode
AT91SAM9M10-G45-EK
325
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
25.5.1
Switch from Internal RC Oscillator to the 32768 Hz Crystal
To switch from internal RC oscillator to the 32768 Hz crystal, the programmer must execute the following
sequence:
sequence:
• Switch the master clock to a source different from slow clock (PLLA or PLLB or Main Oscillator) through the
Power management Controller.
• Enable the 32768 Hz oscillator by setting the bit OSCEN to 1.
• Wait
32768 Hz Startup Time for clock stabilization (software loop)
• Switch from internal RC to 32768Hz by setting the bit OSCSEL to 1.
• Wait 5 slow clock cycles for internal resynchronization
• Disable the RC oscillator by setting the bit RCEN to 0.
25.5.2
Bypass the 32768 Hz Oscillator
The following step must be added to bypass the 32768Hz Oscillator.
• An external clock must be connected on XIN32.
• Enable the bypass path OSC32BYP bit set to 1.
• Disable the 32768 Hz oscillator by setting the bit OSC32EN to 0.
25.5.3
Switch from 32768 Hz Crystal to the Internal RC oscillator
The same procedure must be followed to switch from 32768Hz crystal to the internal RC oscillator.
• Switch the master clock to a source different from slow clock (PLLA or PLLB or Main Oscillator)
• Enable the internal RC oscillator by setting the bit RCEN to 1.
• Wait
internal RC Startup Time for clock stabilization (software loop)
• Switch from 32768Hz oscillator to internal RC by setting the bit OSCSEL to 0
• Wait 5 slow clock cycles for internal resynchronization
• Disable the 32768Hz oscillator by setting the bit OSC32EN to 0