SAM3U2E Atmel Corporation, SAM3U2E Datasheet - Page 784

• Manufacturer Part Number: SAM3U2E
• Manufacturer: Atmel Corporation

Specifications of SAM3U2E

• Flash (kbytes): 128 Kbytes
• Pin Count: 144
• Max. Operating Frequency: 96 MHz
• Cpu: Cortex-M3
• # Of Touch Channels: 57
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 96
• Ext Interrupts: 96
• Usb Transceiver: 1
• Quadrature Decoder Channels: 1
• Usb Speed: Hi-Speed
• Usb Interface: Device
• Spi: 5
• Twi (i2c): 2
• Uart: 5
• Ssc: 1
• Sd / Emmc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 12
• Adc Speed (ksps): 384
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 36
• Self Program Memory: YES
• External Bus Interface: 1
• Dram Memory: No
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 1.62 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 3
• Output Compare Channels: 3
• Input Capture Channels: 3
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

36.6.14.5
784
784
SAM3U Series
SAM3U Series
Speed Measurement
In parallel, the number of edges are accumulated on timer/counter channel 0 and can be read on
the TC_CV0 register.
Therefore, the accurate position can be read on both TC_CV registers and concatenated to form
a 32-bit word.
The timer/counter channel 0 is cleared for each increment of IDX count value.
Depending on the quadrature signals, the direction is decoded and allows to count up or down in
timer/counter channels 0 and 1. The direction status is reported on TC_QISR register.
When SPEEDEN is set in TC_BMR register, the speed measure is enabled on channel 0.
A time base must be defined on channel 2 by writing the TC_RC2 period register. Channel 2
must be configured in waveform mode (WAVE bit field set) in TC_CMR2 register. WAVSEL bit
field must be defined with 0x10 to clear the counter by comparison and matching with TC_RC
value. ACPC field must be defined at 0x11 to toggle TIOA output.
This time base is automatically fed back to TIOA of channel 0 when QDEN and SPEEDEN are
set.
Channel 0 must be configured in capture mode (WAVE = 0 in TC_CMR0). ABETRG bit field of
TC_CMR0 must be configured at 1 to get TIOA as a trigger for this channel.
EDGTRG can be set to 0x01, to clear the counter on a rising edge of the TIOA signal and LDRA
field must be set accordingly to 0x01, to load TC_RA0 at the same time as the counter is cleared
(LDRB must be set to 0x01). As a consequence, at the end of each time base period the differ-
entiation required for the speed calculation is performed.
The process must be started by configuring the TC_CR register with CLKEN and SWTRG.
The speed can be read on TC_RA0 register in TC_CMR0.
Channel 1 can still be used to count the number of revolutions of the motor.
6430E–ATARM–29-Aug-11
6430E–ATARM–29-Aug-11