ATMEGA8A-MUR Atmel, ATMEGA8A-MUR Datasheet - Page 216

• Manufacturer Part Number: ATMEGA8A-MUR
• Description: MCU AVR 8KB FLASH 16MHZ 32QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8A-MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• 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

23.6
8159D–AVR–02/11
Entering the Boot Loader Program
Table 23-2.
Note:
Table 23-3.
Note:
Entering the Boot Loader takes place by a jump or call from the application program. This may
be initiated by a trigger such as a command received via USART, or SPI interface. Alternatively,
the Boot Reset Fuse can be programmed so that the Reset Vector is pointing to the Boot Flash
start address after a reset. In this case, the Boot Loader is started after a reset. After the applica-
tion code is loaded, the program can start executing the application code. Note that the fuses
cannot be changed by the MCU itself. This means that once the Boot Reset Fuse is pro-
grammed, the Reset Vector will always point to the Boot Loader Reset and the fuse can only be
changed through the serial or parallel programming interface.
BLB0
Mode
BLB1
Mode
1
2
3
4
1
2
3
4
1. “1” means unprogrammed, “0” means programmed
1. “1” means unprogrammed, “0” means programmed
BLB02
BLB12
1
1
0
0
1
1
0
0
Boot Lock Bit0 Protection Modes (Application Section)
Boot Lock Bit1 Protection Modes (Boot Loader Section)
BLB01
BLB11
1
0
0
1
1
0
0
1
Protection
No restrictions for SPM or LPM accessing the Application section.
SPM is not allowed to write to the Application section.
SPM is not allowed to write to the Application section, and LPM
executing from the Boot Loader section is not allowed to read from the
Application section. If Interrupt Vectors are placed in the Boot Loader
section, interrupts are disabled while executing from the Application
section.
LPM executing from the Boot Loader section is not allowed to read
from the Application section. If Interrupt Vectors are placed in the Boot
Loader section, interrupts are disabled while executing from the
Application section.
Protection
No restrictions for SPM or LPM accessing the Boot Loader section.
SPM is not allowed to write to the Boot Loader section.
SPM is not allowed to write to the Boot Loader section, and LPM
executing from the Application section is not allowed to read from the
Boot Loader section. If Interrupt Vectors are placed in the Application
section, interrupts are disabled while executing from the Boot Loader
section.
LPM executing from the Application section is not allowed to read from
the Boot Loader section. If Interrupt Vectors are placed in the
Application section, interrupts are disabled while executing from the
Boot Loader section.
(1)
(1)
ATmega8A
216