ATMEGA168-20MU Atmel, ATMEGA168-20MU Datasheet - Page 14

IC AVR MCU 16K 20MHZ 32-QFN

ATMEGA168-20MU

Manufacturer Part Number
ATMEGA168-20MU
Description
IC AVR MCU 16K 20MHZ 32-QFN
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA168-20MU

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
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
32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
Processor Series
ATMEGA16x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
1 KB
Interface Type
2-Wire, SPI, USART, Serial
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
23
Number Of Timers
3
Operating Supply Voltage
2.7 V to 5.5 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
Minimum Operating Temperature
- 40 C
On-chip Adc
10 bit, 8 Channel
A/d Inputs
8-Channel, 10-Bit
Cpu Speed
20 MIPS
Eeprom Memory
512 Bytes
Input Output
23
Interface
I2C/SPI/UART/USART
Memory Type
Flash
Number Of Bits
8
Package Type
32-pin MLF
Programmable Memory
16K Bytes
Timers
2-8-bit, 1-16-bit
Voltage, Range
4.5-5.5 V
Cpu Family
ATmega
Device Core
AVR
Device Core Size
8b
Frequency (max)
20MHz
Total Internal Ram Size
1KB
# I/os (max)
23
Number Of Timers - General Purpose
3
Operating Supply Voltage (typ)
3.3/5V
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
2.7V
Instruction Set Architecture
RISC
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
32
Controller Family/series
AVR MEGA
No. Of I/o's
23
Eeprom Memory Size
512Byte
Ram Memory Size
1KB
No. Of Timers
3
Rohs Compliant
Yes
Package
32MLF EP
Family Name
ATmega
Maximum Speed
20 MHz
For Use With
ATSTK600-TQFP32 - STK600 SOCKET/ADAPTER 32-TQFPATSTK600-DIP40 - STK600 SOCKET/ADAPTER 40-PDIP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATAVRISP2 - PROGRAMMER AVR IN SYSTEMATJTAGICE2 - AVR ON-CHIP D-BUG SYSTEM
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA168-20MU
Quantity:
3 000
6.8
Reset and Interrupt Handling
The AVR provides several different interrupt sources. These interrupts and the separate Reset
Vector each have a separate program vector in the program memory space. All interrupts are
assigned individual enable bits which must be written logic one together with the Global Interrupt
Enable bit in the Status Register in order to enable the interrupt. Depending on the Program
Counter value, interrupts may be automatically disabled when Boot Lock bits BLB02 or BLB12
are programmed. This feature improves software security. See the section
“Memory Program-
ming” on page 284
for details.
The lowest addresses in the program memory space are by default defined as the Reset and
Interrupt Vectors. The complete list of vectors is shown in
“Interrupts” on page
55. The list also
determines the priority levels of the different interrupts. The lower the address the higher is the
priority level. RESET has the highest priority, and next is INT0 – the External Interrupt Request
0. The Interrupt Vectors can be moved to the start of the Boot Flash section by setting the IVSEL
bit in the MCU Control Register (MCUCR). Refer to
“Interrupts” on page 55
for more information.
The Reset Vector can also be moved to the start of the Boot Flash section by programming the
BOOTRST Fuse, see
“Boot Loader Support – Read-While-Write Self-Programming, ATmega88
and ATmega168” on page
268.
When an interrupt occurs, the Global Interrupt Enable I-bit is cleared and all interrupts are dis-
abled. The user software can write logic one to the I-bit to enable nested interrupts. All enabled
interrupts can then interrupt the current interrupt routine. The I-bit is automatically set when a
Return from Interrupt instruction – RETI – is executed.
There are basically two types of interrupts. The first type is triggered by an event that sets the
Interrupt Flag. For these interrupts, the Program Counter is vectored to the actual Interrupt Vec-
tor in order to execute the interrupt handling routine, and hardware clears the corresponding
Interrupt Flag. Interrupt Flags can also be cleared by writing a logic one to the flag bit position(s)
to be cleared. If an interrupt condition occurs while the corresponding interrupt enable bit is
cleared, the Interrupt Flag will be set and remembered until the interrupt is enabled, or the flag is
cleared by software. Similarly, if one or more interrupt conditions occur while the Global Interrupt
Enable bit is cleared, the corresponding Interrupt Flag(s) will be set and remembered until the
Global Interrupt Enable bit is set, and will then be executed by order of priority.
The second type of interrupts will trigger as long as the interrupt condition is present. These
interrupts do not necessarily have Interrupt Flags. If the interrupt condition disappears before the
interrupt is enabled, the interrupt will not be triggered.
When the AVR exits from an interrupt, it will always return to the main program and execute one
more instruction before any pending interrupt is served.
Note that the Status Register is not automatically stored when entering an interrupt routine, nor
restored when returning from an interrupt routine. This must be handled by software.
When using the CLI instruction to disable interrupts, the interrupts will be immediately disabled.
No interrupt will be executed after the CLI instruction, even if it occurs simultaneously with the
CLI instruction. The following example shows how this can be used to avoid interrupts during the
timed EEPROM write sequence.
ATmega48/88/168
14
2545S–AVR–07/10

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