ATMEGA406-1AAU Atmel, ATMEGA406-1AAU Datasheet - Page 10

• Manufacturer Part Number: ATMEGA406-1AAU
• Description: IC AVR MCU 40K 1MHZ 48LQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA406-1AAU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 1MHz
• Connectivity: I²C
• Peripherals: POR, WDT
• Number Of I /o: 18
• Program Memory Size: 40KB (20K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 25 V
• Data Converters: A/D 10x12b
• Oscillator Type: Internal
• Operating Temperature: -30°C ~ 85°C
• Package / Case: 48-LQFP
• Processor Series: ATMEGA48x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: 2-Wire
• Maximum Clock Frequency: 1 MHz
• Number Of Programmable I/os: 18
• Number Of Timers: 2
• 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: - 30 C
• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 1MHz
• Total Internal Ram Size: 2KB
• # I/os (max): 18
• Number Of Timers - General Purpose: 2
• Operating Supply Voltage (typ): 5/9/12/15/18/24V
• Operating Supply Voltage (max): 25V
• Operating Supply Voltage (min): 4V
• On-chip Adc: 10-chx12-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -30C to 85C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 48
• Package Type: LQFP
• Controller Family/series: AVR MEGA
• No. Of I/o's: 18
• Eeprom Memory Size: 512Byte
• Ram Memory Size: 2KB
• Cpu Speed: 1MHz
• Rohs Compliant: Yes
• For Use With: 770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG770-1005 - ISP 4PORT FOR ATMEL AVR MCU JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.4
5.4.1
10
Status Register
ATmega406
SREG – AVR Status Register
The Status Register contains information about the result of the most recently executed arith-
metic instruction. This information can be used for altering program flow in order to perform
conditional operations. Note that the Status Register is updated after all ALU operations, as
specified in the ”AVR Instruction Set” description. This will in many cases remove the need for
using the dedicated compare instructions, resulting in faster and more compact code.
The Status Register is not automatically stored when entering an interrupt routine and restored
when returning from an interrupt. This must be handled by software.
The AVR Status Register – SREG – is defined as:
• Bit 7 – I: Global Interrupt Enable
The Global Interrupt Enable bit must be set for the interrupts to be enabled. The individual inter-
rupt enable control is then performed in separate control registers. If the Global Interrupt Enable
Register is cleared, none of the interrupts are enabled independent of the individual interrupt
enable settings. The I-bit is cleared by hardware after an interrupt has occurred, and is set by
the RETI instruction to enable subsequent interrupts. The I-bit can also be set and cleared by
the application with the SEI and CLI instructions, as described in the ”AVR Instruction Set”
description.
• Bit 6 – T: Bit Copy Storage
The Bit Copy instructions BLD (Bit LoaD) and BST (Bit STore) use the T-bit as source or desti-
nation for the operated bit. A bit from a register in the Register File can be copied into T by the
BST instruction, and a bit in T can be copied into a bit in a register in the Register File by the
BLD instruction.
• Bit 5 – H: Half Carry Flag
The Half Carry Flag H indicates a Half Carry in some arithmetic operations. Half Carry Is useful
in BCD arithmetic. See the ”AVR Instruction Set” for detailed information.
• Bit 4 – S: Sign Bit, S = N
The S-bit is always an exclusive or between the negative flag N and the Two’s Complement
Overflow Flag V. See the ”AVR Instruction Set” for detailed information.
• Bit 3 – V: Two’s Complement Overflow Flag
The Two’s Complement Overflow Flag V supports two’s complement arithmetics. See the ”AVR
Instruction Set” for detailed information.
• Bit 2 – N: Negative Flag
The Negative Flag N indicates a negative result in an arithmetic or logic operation. See the ”AVR
Instruction Set” for detailed information.
Bit
0x3F (0x5F)
Read/Write
Initial Value
R/W
7
0
I
R/W
6
T
0
⊕
V
R/W
H
5
0
R/W
S
4
0
R/W
V
3
0
R/W
N
2
0
R/W
Z
1
0
R/W
C
0
0
2548E–AVR–07/06
SREG