ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 157

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 14
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 26
• Ext Interrupts: 13
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 3.3
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

15.10 Fault Protection Unit
7766F–AVR–11/10
Figure 15-18. Timer/Counter Timing Diagram, Setting of OCF1x, with Prescaler (f
Figure 15-19. Timer/Counter Timing Diagram, with Prescaler (f
The Timer/Counter4 incorporates a Fault Protection unit that can disable the PWM output pins, if
an external event is triggered. The external signal indicating an event can be applied via the
external interrupt INT0 pin or alternatively, via the analog-comparator unit. The Fault Protection
unit is illustrated by the block diagram shown in
that are not directly a part of the Fault Protection unit are gray shaded.
Figure 15-20. Fault Protection Unit Block Diagram
When the Fault Protection mode is enabled by the Fault Protection Enable (FPEN4) bit and a
change of the logic level (an event) occurs on the external interrupt pin (INT0), alternatively on
the Analog Comparator output (ACO), and this change confirms to the setting of the edge detec-
tor, a Fault Protection mode will be triggered. When a Fault Protection is triggered, the COM4x
bits are cleared, Output Comparators are disconnected from the PWM output pins and the
PORTB register bits are connected on the PWM output pins. The Fault Protection Enable
(FPEN4) is automatically cleared at the same system clock as the COM4nx bits are cleared. If
the Fault Protection Interrupt Enable bit (FPIE4) is set, a Fault Protection interrupt is generated
and the FPEN4 bit is cleared. Alternatively the FPEN4 bit can be polled by software to figure out
when the Timer/Counter has entered to Fault Protection mode.
TCNTn
TCNTn
(clk
(clk
TOVn
OCRnx
OCFnx
clk
clk
clk
clk
INT0
PCK
PCK
PCK
Tn
PCK
Tn
/8)
/8)
Comparator
Analog
BOTTOM + 1
ACO*
OCRnx - 1
FPAC4
BOTTOM + 1
Canceler
Noise
OCRnx
FPNC4
OCRnx Value
Figure
FPES4
15-20. The elements of the block diagram
Detector
Edge
OCRnx + 1
BOTTOM
FPEN4
clkT4
ATmega16/32U4
/8)
FAULT_PROTECTION (Int. Req.)
BOTTOM + 1
OCRnx + 2
Timer/Counter4
clkT4
/8)
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