ATMEGA8A-PU Atmel, ATMEGA8A-PU Datasheet - Page 224

• Manufacturer Part Number: ATMEGA8A-PU
• Description: MCU AVR 8K FLASH 16MHZ 28-PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8A-PU

• 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 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Processor Series: ATMEGA8x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 1 KB
• Interface Type: SPI, TWI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 23
• Number Of Timers: 3
• 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: 10 bit, 6 Channel
• Package: 28PDIP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 16 MHz
• Operating Supply Voltage: 3.3|5 V
• Controller Family/series: AVR MEGA
• No. Of I/o's: 23
• Eeprom Memory Size: 512Byte
• Ram Memory Size: 1KB
• Cpu Speed: 16MHz
• Rohs Compliant: Yes
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

23.9
23.9.1
8159D–AVR–02/11
Register Description
Store Program Memory Control Register – SPMCR
The Store Program memory Control Register contains the control bits needed to control the Boot
Loader operations.
• Bit 7 – SPMIE: SPM Interrupt Enable
When the SPMIE bit is written to one, and the I-bit in the Status Register is set (one), the SPM
ready interrupt will be enabled. The SPM ready Interrupt will be executed as long as the SPMEN
bit in the SPMCR Register is cleared.
• Bit 6 – RWWSB: Read-While-Write Section Busy
When a Self-Programming (page erase or page write) operation to the RWW section is initiated,
the RWWSB will be set (one) by hardware. When the RWWSB bit is set, the RWW section can-
not be accessed. The RWWSB bit will be cleared if the RWWSRE bit is written to one after a
Self-Programming operation is completed. Alternatively the RWWSB bit will automatically be
cleared if a page load operation is initiated.
• Bit 5 – Res: Reserved Bit
This bit is a reserved bit in the ATmega8A and always read as zero.
• Bit 4 – RWWSRE: Read-While-Write Section Read Enable
When programming (page erase or page write) to the RWW section, the RWW section is
blocked for reading (the RWWSB will be set by hardware). To re-enable the RWW section, the
user software must wait until the programming is completed (SPMEN will be cleared). Then, if
the RWWSRE bit is written to one at the same time as SPMEN, the next SPM instruction within
four clock cycles re-enables the RWW section. The RWW section cannot be re-enabled while
the Flash is busy with a page erase or a page write (SPMEN is set). If the RWWSRE bit is writ-
ten while the Flash is being loaded, the Flash load operation will abort and the data loaded will
be lost (The page buffer will be cleared when the Read-While-Write section is re-enabled).
• Bit 3 – BLBSET: Boot Lock Bit Set
If this bit is written to one at the same time as SPMEN, the next SPM instruction within four clock
cycles sets Boot Lock Bits, according to the data in R0. The data in R1 and the address in the Z-
pointer are ignored. The BLBSET bit will automatically be cleared upon completion of the lock bit
set, or if no SPM instruction is executed within four clock cycles.
An LPM instruction within three cycles after BLBSET and SPMEN are set in the SPMCR Regis-
ter, will read either the Lock Bits or the Fuse Bits (depending on Z0 in the Z-pointer) into the
destination register. See
details.
Bit
Read/Write
Initial Value
See
Z-pointer during Self-Programming.
SPMIE
R/W
“Addressing the Flash During Self-Programming” on page 217
7
0
RWWSB
R
6
0
“Reading the Fuse and Lock Bits from Software” on page 220
R
5
–
0
RWWSRE
R/W
4
0
BLBSET
R/W
3
0
PGWRT
R/W
2
0
PGERS
R/W
for details about the use of
1
0
ATmega8A
SPMEN
R/W
0
0
SPMCR
224
for