ATMEGA88P-20MUR Atmel, ATMEGA88P-20MUR Datasheet - Page 47

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ATMEGA88P-20MUR

Manufacturer Part Number
ATMEGA88P-20MUR
Description
MCU AVR 8KB FLASH 20MHZ 32QFN
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheet

Specifications of ATMEGA88P-20MUR

Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
23
Program Memory Size
8KB (4K 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
*
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
10. System Control and Reset
10.1
10.2
8025L–AVR–7/10
Resetting the AVR
Reset Sources
During reset, all I/O Registers are set to their initial values, and the program starts execution
from the Reset Vector. For the ATmega168P, the instruction placed at the Reset Vector must be
a JMP – Absolute Jump – instruction to the reset handling routine. For the ATmega48P and
ATmega88P, the instruction placed at the Reset Vector must be an RJMP – Relative Jump –
instruction to the reset handling routine. If the program never enables an interrupt source, the
Interrupt Vectors are not used, and regular program code can be placed at these locations. This
is also the case if the Reset Vector is in the Application section while the Interrupt Vectors are in
the Boot section or vice versa (ATmega88P/168P only). The circuit diagram in
page 48
reset circuitry.
The I/O ports of the AVR are immediately reset to their initial state when a reset source goes
active. This does not require any clock source to be running.
After all reset sources have gone inactive, a delay counter is invoked, stretching the internal
reset. This allows the power to reach a stable level before normal operation starts. The time-out
period of the delay counter is defined by the user through the SUT and CKSEL Fuses. The dif-
ferent selections for the delay period are presented in
The ATmega48P/88P/168P has four sources of reset:
• Power-on Reset. The MCU is reset when the supply voltage is below the Power-on Reset
• External Reset. The MCU is reset when a low level is present on the RESET pin for longer than
• Watchdog System Reset. The MCU is reset when the Watchdog Timer period expires and the
• Brown-out Reset. The MCU is reset when the supply voltage V
threshold (V
the minimum pulse length.
Watchdog System Reset mode is enabled.
threshold (V
shows the reset logic.
POT
BOT
).
) and the Brown-out Detector is enabled.
Table 28-3 on page 314
ATmega48P/88P/168P
”Clock Sources” on page
defines the electrical parameters of the
CC
is below the Brown-out Reset
28.
Figure 10-1 on
47

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