SAM9G20 Atmel Corporation, SAM9G20 Datasheet - Page 176

• Manufacturer Part Number: SAM9G20
• Manufacturer: Atmel Corporation

Specifications of SAM9G20

• Flash (kbytes): 0 Kbytes
• Pin Count: 217
• Max. Operating Frequency: 400 MHz
• Cpu: ARM926
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 96
• Ext Interrupts: 96
• Usb Transceiver: 3
• Usb Speed: Full Speed
• Usb Interface: Host, Device
• Spi: 2
• Twi (i2c): 1
• Uart: 7
• Ssc: 1
• Ethernet: 1
• Sd / Emmc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: Yes
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 95
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 32
• Self Program Memory: NO
• External Bus Interface: 1
• Dram Memory: sdram
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 0.9 to 1.1
• Fpu: No
• Mpu / Mmu: No/Yes
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

21.4.3
176
SAM9G35
Switch from the 32,768 Hz Crystal to Internal 32 kHz RC Oscillator
The same procedure must be followed to switch from a 32,768 Hz crystal to the internal 32 kHz
RC oscillator.
• Switch the master clock to a source different from slow clock (PLL or Main Oscillator).
• Enable the internal 32 kHz RC oscillator for low power by setting the bit RCEN to 1
• Wait internal 32 kHz RC Startup Time for clock stabilization (software loop).
• Switch from 32768 Hz oscillator to internal RC by setting the bit OSCSEL to 0.
• Wait 5 slow clock cycles for internal resynchronization.
• Disable the 32768 Hz oscillator by setting the bit OSC32EN to 0.
• Switch the master clock back to the slow clock domain
11053B–ATARM–22-Sep-11