ATtiny461 Automotive Atmel Corporation, ATtiny461 Automotive Datasheet - Page 111

• Manufacturer Part Number: ATtiny461 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATtiny461 Automotive

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 16
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.25
• Eeprom (bytes): 256
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 150
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

16.9
16.9.1
16.9.2
7753F–AVR–01/11
Fault Protection Unit
Fault Protection Trigger Source
Noise Canceler
The Timer/Counter1 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 16-18. Fault Protection Unit Block Diagram
When the Fault Protection mode is enabled by the Fault Protection Enable (FPEN1) 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 COM1x
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
(FPEN1) is automatically cleared at the same system clock as the COM1nx bits are cleared. If
the Fault Protection Interrupt Enable bit (FPIE1) is set, a Fault Protection interrupt is generated
and the FPEN1 bit is cleared. Alternatively the FPEN1 bit can be polled by software to figure out
when the Timer/Counter has entered to Fault Protection mode.
The main trigger source for the Fault Protection unit is the external interrupt pin (INT0). Alterna-
tively the Analog Comparator output can be used as trigger source for the Fault Protection unit.
The Analog Comparator is selected as trigger source by setting the Fault Protection Analog
Comparator (FPAC1) bit in the Timer/Counter1 Control Register (TCCR1D). Be aware that
changing trigger source can trigger a Fault Protection mode. Therefore it is recommended to
clear the FPF1 flag after changing trigger source, setting edge detector or enabling the Fault
Protection.
Both the external interrupt pin (INT0) and the Analog Comparator output (ACO) inputs are sam-
pled using the same technique as for the T0 pin
also identical. However, when the noise canceler is enabled, additional logic is inserted before
the edge detector, which increases the delay by four system clock cycles. An Input Capture can
also be triggered by software by controlling the port of the INT0 pin.
The noise canceler improves noise immunity by using a simple digital filtering scheme. The
noise canceler input is monitored over four samples, and all four must be equal for changing the
output that in turn is used by the edge detector.
The noise canceler is enabled by setting the Fault Protection Noise Canceler (FPNC1) bit in
Timer/Counter1 Control Register D (TCCR1D). When enabled the noise canceler introduces
additional four system clock cycles of delay from a change applied to the input. The noise can-
celer uses the system clock and is therefore not affected by the prescaler.
INT0
Comparator
Analog
ACO*
FPAC1
ATtiny261/ATtiny461/ATtiny861
Canceler
Noise
FPNC1
Figure
(Figure 13-1 on page
FPES1
16-18. The elements of the block diagram
Detector
Edge
FPEN1
FAULT_PROTECTION (Int. Req.)
70). The edge detector is
Timer/Counter1
111