ATtiny40 Atmel Corporation, ATtiny40 Datasheet - Page 34

• Manufacturer Part Number: ATtiny40
• Manufacturer: Atmel Corporation

Specifications of ATtiny40

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 12 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: Yes
• Max I/o Pins: 18
• Ext Interrupts: 18
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 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): 0.25
• Self Program Memory: NO
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

8.2.3
8.2.4
34
ATtiny40
Watchdog Reset
Brown-out Detection
Figure 8-4.
When the Watchdog times out, it will generate a short reset pulse of one CK cycle duration. On
the falling edge of this pulse, the delay timer starts counting the time-out period t
34
reset time-out.
Figure 8-5.
ATtiny40 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
operation by comparing it to a fixed trigger level. The trigger level for the BOD can be selected
by the BODLEVEL Fuses. The trigger level has a hysteresis to ensure spike free Brown-out
Detection. The hysteresis on the detection level should be interpreted as V
and V
When the BOD is enabled, and V
8-6 on page
trigger level (V
t
The BOD circuit will only detect a drop in V
ger than t
TOUT
for details on operation of the Watchdog Timer and
has expired.
BOT-
CC
CC
BOD
= V
35), the Brown-out Reset is immediately activated. When V
given in
BOT
External Reset During Operation
Watchdog Reset During Operation
BOT+
- V
in
HYST
“System and Reset Characteristics” on page
Figure
/2.
8-6), the delay counter starts the MCU after the Time-out period
CC
decreases to a value below the trigger level (V
CK
CC
if the voltage stays below the trigger level for lon-
Table 21-4 on page 168
168.
CC
BOT+
increases above the
= V
TOUT
CC
8263A–AVR–08/10
for details on
BOT
BOT-
level during
. See
+ V
in
Figure
HYST
page
/2