ATtiny861 Automotive Atmel Corporation, ATtiny861 Automotive Datasheet - Page 44

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ATtiny861 Automotive

Manufacturer Part Number
ATtiny861 Automotive
Description
Manufacturer
Atmel Corporation

Specifications of ATtiny861 Automotive

Flash (kbytes)
8 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)
0.5
Eeprom (bytes)
512
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
9.1
9.1.1
9.2
44
Internal Voltage Reference
Watchdog Timer
ATtiny261/ATtiny461/ATtiny861
Voltage Reference Enable Signals and Start-up Time
ATtiny261/461/861 features an internal bandgap reference. This reference is used for Brown-out
Detection, and it can be used as an input to the Analog Comparator or the ADC.
The voltage reference has a start-up time that may influence the way it should be used. The
start-up time is given in
reference is not always turned on. The reference is on during the following situations:
1. When the BOD is enabled (by programming the BODLEVEL [2..0] Fuse bits).
2. When the bandgap reference is connected to the Analog Comparator (by setting the
3. When the ADC is enabled.
Thus, when the BOD is not enabled, after setting the ACBG bit or enabling the ADC, the user
must always allow the reference to start up before the output from the Analog Comparator or
ADC is used. To reduce power consumption in Power-down mode, the user can avoid the three
conditions above to ensure that the reference is turned off before entering Power-down mode.
The Watchdog Timer is clocked from an On-chip Oscillator which runs at 128 kHz. By controlling
the Watchdog Timer prescaler, the Watchdog Reset interval can be adjusted as shown in
9-4 on page
Watchdog Timer is also reset when it is disabled and when a Chip Reset occurs. Ten different
clock cycle periods can be selected to determine the reset period. If the reset period expires
without another Watchdog Reset, the ATtiny261/461/861 resets and executes from the Reset
Vector. For timing details on the Watchdog Reset, refer to
The Watchdog Timer can also be configured to generate an interrupt instead of a reset. This can
be very helpful when using the Watchdog to wake-up from Power-down.
To prevent unintentional disabling of the Watchdog or unintentional change of time-out period,
two different safety levels are selected by the fuse WDTON as shown in Table 9-2. Refer to
“Timed Sequences for Changing the Configuration of the Watchdog Timer” on page 45
details.
Table 9-2.
WDTON
Unprogrammed
Programmed
ACBG bit in ACSR).
48. The WDR – Watchdog Reset – instruction resets the Watchdog Timer. The
WDT Configuration as a Function of the Fuse Settings of WDTON
Safety
Level
1
2
“System and Reset Characteristics” on page
WDT Initial
State
Disabled
Enabled
How to Disable the
WDT
Timed sequence
Always enabled
Table 9-4 on page
190. To save power, the
How to Change
Time-out
No limitations
Timed sequence
48.
7753F–AVR–01/11
Table
for

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