ATmega1280 Atmel Corporation, ATmega1280 Datasheet - Page 324

• Manufacturer Part Number: ATmega1280
• Manufacturer: Atmel Corporation

Specifications of ATmega1280

• Flash (kbytes): 128 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 86
• Ext Interrupts: 32
• Usb Speed: No
• Usb Interface: No
• Spi: 5
• Twi (i2c): 1
• Uart: 4
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 8
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 16
• Input Capture Channels: 4
• Pwm Channels: 15
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

29.6.3
29.6.4
29.6.5
29.6.6
29.6.7
2549N–AVR–05/11
Performing a Page Write
Using the SPM Interrupt
Consideration While Updating BLS
Prevent Reading the RWW Section During Self-Programming
Setting the Boot Loader Lock Bits by SPM
To execute Page Write, set up the address in the Z-pointer, write “X0000101” to SPMCSR and
execute SPM within four clock cycles after writing SPMCSR. The data in R1 and R0 is ignored.
The page address must be written to PCPAGE. Other bits in the Z-pointer must be written to
zero during this operation.
•
•
If the SPM interrupt is enabled, the SPM interrupt will generate a constant interrupt when the
SPMEN bit in SPMCSR is cleared. This means that the interrupt can be used instead of polling
the SPMCSR Register in software. When using the SPM interrupt, the Interrupt Vectors should
be moved to the BLS section to avoid that an interrupt is accessing the RWW section when it is
blocked for reading. How to move the interrupts is described in
Special care must be taken if the user allows the Boot Loader section to be updated by leaving
Boot Lock bit11 unprogrammed. An accidental write to the Boot Loader itself can corrupt the
entire Boot Loader, and further software updates might be impossible. If it is not necessary to
change the Boot Loader software itself, it is recommended to program the Boot Lock bit11 to
protect the Boot Loader software from any internal software changes.
During Self-Programming (either Page Erase or Page Write), the RWW section is always
blocked for reading. The user software itself must prevent that this section is addressed during
the self programming operation. The RWWSB in the SPMCSR will be set as long as the RWW
section is busy. During Self-Programming the Interrupt Vector table should be moved to the BLS
as described in
the RWW section after the programming is completed, the user software must clear the
RWWSB by writing the RWWSRE. See
page 327
To set the Boot Loader Lock bits and general Lock bits, write the desired data to R0, write
“X0001001” to SPMCSR and execute SPM within four clock cycles after writing SPMCSR.
See
Boot Loader bits affect the Flash access.
If bits 5:0 in R0 are cleared (zero), the corresponding Lock bit will be programmed if an SPM
instruction is executed within four cycles after BLBSET and SPMEN are set in SPMCSR. The Z-
pointer is don’t care during this operation, but for future compatibility it is recommended to load
the Z-pointer with 0x0001 (same as used for reading the lO
also recommended to set bits 7 and 6 in R0 to “1” when writing the Lock bits. When program-
ming the Lock bits the entire Flash can be read during the operation.
Bit
R0
Page Write to the RWW section: The NRWW section can be read during the Page Write
Page Write to the NRWW section: The CPU is halted during the operation
Table 29-2 on page 321
for an example.
“Interrupts” on page
7
1
6
1
and
ATmega640/1280/1281/2560/2561
BLB12
Table 29-3 on page 321
5
105, or the interrupts must be disabled. Before addressing
“Simple Assembly Code Example for a Boot Loader” on
BLB11
4
BLB02
3
for how the different settings of the
ck
BLB01
bits). For future compatibility it is
“Interrupts” on page
2
LB2
1
LB1
0
105.
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