AT90LS8535-4MC Atmel, AT90LS8535-4MC Datasheet - Page 19
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AT90LS8535-4MC
Manufacturer Part Number
AT90LS8535-4MC
Description
IC MCU 8K FLASH 4MHZ COM 44-QFN
Manufacturer
Atmel
Series
AVR® 90LSr
Specifications of AT90LS8535-4MC
Core Processor
AVR
Core Size
8-Bit
Speed
4MHz
Connectivity
SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
32
Program Memory Size
8KB (4K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
512 x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 6 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
0°C ~ 70°C
Package / Case
44-VQFN Exposed Pad
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Status Register – SREG
1041H–11/01
The AVR Status Register (SREG) at I/O space location $3F ($5F) 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
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 arithmetics. 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 logic 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 ($5F)
Read/Write
Initial Value
R/W
7
0
I
R/W
T
6
0
⊄⊕
V
R/W
H
5
0
R/W
4
S
0
R/W
3
V
0
R/W
N
2
0
AT90S/LS8535
R/W
Z
1
0
R/W
C
0
0
SREG
19