ATmega48PA Atmel Corporation, ATmega48PA Datasheet - Page 50

• Manufacturer Part Number: ATmega48PA
• Manufacturer: Atmel Corporation

Specifications of ATmega48PA

• Flash (kbytes): 4 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 24
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• 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): 256
• Self Program Memory: NO
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• 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: 3
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

11.4
11.5
8271D–AVR–05/11
External Reset
Brown-out Detection
Figure 11-3. MCU Start-up, RESET Extended Externally
An External Reset is generated by a low level on the RESET pin. Reset pulses longer than the
minimum pulse width (see
reset, even if the clock is not running. Shorter pulses are not guaranteed to generate a reset.
When the applied signal reaches the Reset Threshold Voltage – V
delay counter starts the MCU after the Time-out period – t
can be disabled by the RSTDISBL fuse, see
Figure 11-4. External Reset During Operation
ATmega48A/PA/88A/PA/168A/PA/328/P has an On-chip Brown-out Detection (BOD) circuit for
monitoring the V
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 inter-
preted as V
decreases to a value below the trigger level (V
Reset is immediately activated. When V
5 on page
The BOD circuit will only detect a drop in V
ger than t
INTERNAL
TIME-OUT
RESET
RESET
BOD
V
51), the delay counter starts the MCU after the Time-out period t
CC
CC
BOT+
given in
= V
CC
level during operation by comparing it to a fixed trigger level. The trigger level
BOT
ATmega48A/PA/88A/PA/168A/PA/328/P
”System and Reset Characteristics” on page
+ V
HYST
V
”System and Reset Characteristics” on page
POT
/2 and V
BOT-
CC
increases above the trigger level (V
CC
= V
Table 28-7 on page
if the voltage stays below the trigger level for lon-
V
BOT
BOT-
RST
t
- V
TOUT
in
HYST
Figure 11-5 on page
TOUT
/2.When the BOD is enabled, and V
– has expired. The External Reset
299.
RST
324.
– on its positive edge, the
TOUT
324) will generate a
51), the Brown-out
BOT+
has expired.
in
Figure 11-
50
CC