ATTINY28L-4PU Atmel, ATTINY28L-4PU Datasheet - Page 6

• Manufacturer Part Number: ATTINY28L-4PU
• Description: IC MCU 2K FLASH 4MHZ 28-DIP
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY28L-4PU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Peripherals: POR, WDT
• Number Of I /o: 11
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Processor Series: ATTINY2x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 32 B
• Maximum Clock Frequency: 4 MHz
• Number Of Programmable I/os: 11
• Number Of Timers: 1
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Package: 28PDIP
• Device Core: AVR
• Family Name: ATtiny
• Maximum Speed: 4 MHz
• Ram Size: 32 Byte
• For Use With: ATSTK600-DIP40 - STK600 SOCKET/ADAPTER 40-PDIPATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Ram Size: -
• Data Converters: -
• Connectivity: -
• Lead Free Status / Rohs Status: Details

Status Register
Status Register – SREG
6
ATtiny28L/V
The AVR status register (SREG) at I/O space location $3F is defined as:
• Bit 7 – I: Global Interrupt Enable
The global interrupt enable bit must be set (one) for the interrupts to be enabled. The
individual interrupt enable control is then performed in separate control registers. If the
global interrupt enable register is cleared (zero), none of the interrupts are enabled inde-
pendent 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.
• Bit 6 – T: Bit Copy Storage
The bit copy instructions BLD (Bit LoaD) and BST (Bit STore) use the T-bit as source
and destination 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. See the
Instruction Set description for detailed information.
• Bit 4 – S: Sign Bit, S = N ⊕ V
The S-bit is always an exclusive or between the negative flag N and the two’s comple-
ment overflow flag V. See the Instruction Set description for detailed information.
• Bit 3 – V: Two’s Complement Overflow Flag
The two’s complement overflow flag V supports two’s complement arithmetic. See the
Instruction Set description for detailed information.
• Bit 2 – N: Negative Flag
The negative flag N indicates a negative result from an arithmetical or logical operation.
See the Instruction Set description for detailed information.
• Bit 1 – Z: Zero Flag
The zero flag Z indicates a zero result from an arithmetical or logical operation. See the
Instruction Set description for detailed information.
• Bit 0 – C: Carry Flag
The carry flag C indicates a carry in an arithmetical or logical operation. See the Instruc-
tion Set description for detailed information.
Note that the status register is not automatically stored when entering an interrupt rou-
tine and restored when returning from an interrupt routine. This must be handled by
software.
Bit
$3F
Read/Write
Initial Value
R/W
7
0
I
R/W
6
T
0
R/W
H
5
0
R/W
S
4
0
R/W
V
3
0
R/W
2
N
0
R/W
1
Z
0
R/W
1062F–AVR–07/06
C
0
0
SREG