SAM3U1C Atmel Corporation, SAM3U1C Datasheet - Page 176

• Manufacturer Part Number: SAM3U1C
• Manufacturer: Atmel Corporation

Specifications of SAM3U1C

• Flash (kbytes): 64 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 96 MHz
• Cpu: Cortex-M3
• # Of Touch Channels: 28
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 57
• Ext Interrupts: 57
• Usb Transceiver: 1
• Quadrature Decoder Channels: 1
• Usb Speed: Hi-Speed
• Usb Interface: Device
• Spi: 4
• Twi (i2c): 1
• Uart: 4
• Ssc: 1
• Sd / Emmc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 12
• Adc Speed (ksps): 384
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 20
• 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

13.19.9
13.19.9.1
176
SAM3U Series
Level-sensitive interrupts
Hardware and software control of interrupts
The processor supports level-sensitive interrupts.
A level-sensitive interrupt is held asserted until the peripheral deasserts the interrupt signal. Typ-
ically this happens because the ISR accesses the peripheral, causing it to clear the interrupt
request.
When the processor enters the ISR, it automatically removes the pending state from the inter-
rupt, see
signal is not deasserted before the processor returns from the ISR, the interrupt becomes pend-
ing again, and the processor must execute its ISR again. This means that the peripheral can
hold the interrupt signal asserted until it no longer needs servicing.
The Cortex-M3 latches all interrupts. A peripheral interrupt becomes pending for one of the fol-
lowing reasons:
A pending interrupt remains pending until one of the following:
The processor enters the ISR for the interrupt. This changes the state of the interrupt from pend-
ing to active. Then:
For a level-sensitive interrupt, if the interrupt signal is still asserted, the state of the interrupt
does not change. Otherwise, the state of the interrupt changes to inactive.
• the NVIC detects that the interrupt signal is HIGH and the interrupt is not active
• the NVIC detects a rising edge on the interrupt signal
• software writes to the corresponding interrupt set-pending register bit, see
• Software writes to the corresponding interrupt clear-pending register bit.
pending Registers” on page
Trigger Interrupt Register” on page
– For a level-sensitive interrupt, when the processor returns from the ISR, the NVIC
– If the interrupt signal is not pulsed while the processor is in the ISR, when the
samples the interrupt signal. If the signal is asserted, the state of the interrupt
changes to pending, which might cause the processor to immediately re-enter the
ISR. Otherwise, the state of the interrupt changes to inactive.
processor returns from the ISR the state of the interrupt changes to inactive.
“Hardware and software control of
169, or to the STIR to make an SGI pending, see
175.
interrupts”. For a level-sensitive interrupt, if the
6430E–ATARM–29-Aug-11
“Interrupt Set-
“Software