ATMEGA169-16AI Atmel, ATMEGA169-16AI Datasheet - Page 41

• Manufacturer Part Number: ATMEGA169-16AI
• Description: IC AVR MCU 16K 16MHZ IND TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA169-16AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• For Use With: ATAVRBFLY - KIT EVALUATION AVR BUTTERFLYATSTK502 - MOD EXPANSION AVR STARTER 500
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Watchdog Reset
MCU Status Register –
MCUSR
2514P–AVR–07/06
When the BOD is enabled, and V
in Figure 18), the Brown-out Reset is immediately activated. When V
the trigger level (V
out period t
The BOD circuit will only detect a drop in V
for longer than t
Figure 18. Brown-out Reset During Operation
When the Watchdog times out, it will generate a short reset pulse of one CK cycle dura-
tion. On the falling edge of this pulse, the delay timer starts counting the Time-out period
t
Figure 19. Watchdog Reset During Operation
The MCU Status Register provides information on which reset source caused an MCU
reset.
• Bit 4 – JTRF: JTAG Reset Flag
This bit is set if a reset is being caused by a logic one in the JTAG Reset Register
selected by the JTAG instruction AVR_RESET. This bit is reset by a Power-on Reset, or
by writing a logic zero to the flag.
TOUT
Bit
Read/Write
Initial Value
. Refer to page 43 for details on operation of the Watchdog Timer.
CC
INTERNAL
TOUT
TIME-OUT
RESET
RESET
BOD
V
R
has expired.
7
–
0
CC
BOT+
given in Table 16.
in Figure 18), the delay counter starts the MCU after the Time-
R
6
–
0
R
5
–
0
CC
V
CK
BOT-
decreases to a value below the trigger level (V
JTRF
R/W
4
CC
if the voltage stays below the trigger level
WDRF
R/W
3
See Bit Description
BORF
R/W
V
t
2
TOUT
BOT+
ATmega169/V
EXTRF
R/W
1
CC
increases above
PORF
R/W
0
MCUSR
BOT-
41