SAM9G45 Atmel Corporation, SAM9G45 Datasheet - Page 741

• Manufacturer Part Number: SAM9G45
• Manufacturer: Atmel Corporation

Specifications of SAM9G45

• Flash (kbytes): 0 Kbytes
• Pin Count: 324
• Max. Operating Frequency: 400 MHz
• Cpu: ARM926
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 160
• Ext Interrupts: 160
• Usb Transceiver: 3
• Usb Speed: Hi-Speed
• Usb Interface: Host, Device
• Spi: 2
• Twi (i2c): 2
• Uart: 5
• Lin: 4
• Ssc: 2
• Ethernet: 1
• Sd / Emmc: 2
• Graphic Lcd: Yes
• Video Decoder: No
• Camera Interface: Yes
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 440
• Resistive Touch Screen: Yes
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 64
• Self Program Memory: NO
• External Bus Interface: 2
• Dram Memory: DDR2/LPDDR, SDRAM/LPSDR
• 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
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

37.6.3
37.6.3.1
37.6.3.2
37.6.3.3
11053B–ATARM–22-Sep-11
11053B–ATARM–22-Sep-11
PWM Controller Operations
Initialization
Changing the Duty Cycle or the Period
Source Clock Selection Criteria
Before enabling the output channel, this channel must have been configured by the software
application:
It is possible to synchronize different channels by enabling them at the same time by means of
writing simultaneously several CHIDx bits in the PWM_ENA register.
The large number of source clocks can make selection difficult. The relationship between the
value in the Period Register (PWM_CPRDx) and the Duty Cycle Register (PWM_CDTYx) can
help the user in choosing. The event number written in the Period Register gives the PWM accu-
racy. The Duty Cycle quantum cannot be lower than 1/PWM_CPRDx value. The higher the value
of PWM_CPRDx, the greater the PWM accuracy.
For example, if the user sets 15 (in decimal) in PWM_CPRDx, the user is able to set a value
between 1 up to 14 in PWM_CDTYx Register. The resulting duty cycle quantum cannot be lower
than 1/15 of the PWM period.
It is possible to modulate the output waveform duty cycle or period.
To prevent unexpected output waveform, the user must use the update register (PWM_CUPDx)
to change waveform parameters while the channel is still enabled. The user can write a new
period value or duty cycle value in the update register (PWM_CUPDx). This register holds the
new value until the end of the current cycle and updates the value for the next cycle. Depending
on the CPD field in the PWM_CMRx register, PWM_CUPDx either updates PWM_CPRDx or
PWM_CDTYx. Note that even if the update register is used, the period must not be smaller than
the duty cycle.
• Configuration of the clock generator if DIVA and DIVB are required
• Selection of the clock for each channel (CPRE field in the PWM_CMRx register)
• Configuration of the waveform alignment for each channel (CALG field in the PWM_CMRx
• Configuration of the period for each channel (CPRD in the PWM_CPRDx register). Writing in
• Configuration of the duty cycle for each channel (CDTY in the PWM_CDTYx register).
• Configuration of the output waveform polarity for each channel (CPOL in the PWM_CMRx
• Enable Interrupts (Writing CHIDx in the PWM_IER register)
• Enable the PWM channel (Writing CHIDx in the PWM_ENA register)
• In such a situation, all channels may have the same clock selector configuration and the
register)
PWM_CPRDx Register is possible while the channel is disabled. After validation of the
channel, the user must use PWM_CUPDx Register to update PWM_CPRDx as explained
below.
Writing in PWM_CDTYx Register is possible while the channel is disabled. After validation of
the channel, the user must use PWM_CUPDx Register to update PWM_CDTYx as explained
below.
register)
same period specified.
SAM9G35
SAM9G35
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