ATmega329P Atmel Corporation, ATmega329P Datasheet - Page 290

• Manufacturer Part Number: ATmega329P
• Manufacturer: Atmel Corporation

Specifications of ATmega329P

• Flash (kbytes): 32 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 54
• Ext Interrupts: 17
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Segment Lcd: 100
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• 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: 3
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

26.8.10
26.8.11
8021G–AVR–03/11
Preventing Flash Corruption
Programming Time for Flash when Using SPM
When reading the Extended Fuse byte, load 0x0002 in the Z-pointer. When an LPM instruction
is executed within three cycles after the BLBSET and SPMEN bits are set in the SPMCSR, the
value of the Extended Fuse byte (EFB) will be loaded in the destination register as shown below.
Refer to
byte.
Fuse and Lock bits that are programmed, will be read as zero. Fuse and Lock bits that are
unprogrammed, will be read as one.
During periods of low V
too low for the CPU and the Flash to operate properly. These issues are the same as for board
level systems using the Flash, and the same design solutions should be applied.
A Flash program corruption can be caused by two situations when the voltage is too low. First, a
regular write sequence to the Flash requires a minimum voltage to operate correctly. Secondly,
the CPU itself can execute instructions incorrectly, if the supply voltage for executing instructions
is too low.
Flash corruption can easily be avoided by following these design recommendations (one is
sufficient):
1. If there is no need for a Boot Loader update in the system, program the Boot Loader Lock
2. Keep the AVR RESET active (low) during periods of insufficient power supply voltage.
3. Keep the AVR core in Power-down sleep mode during periods of low V
The calibrated RC Oscillator is used to time Flash accesses.
gramming time for Flash accesses from the CPU.
Table 26-5.
Note:
Bit
Rd
Bit
Rd
Flash write (Page Erase, Page Write, and
write Lock bits by SPM)
bits to prevent any Boot Loader software updates.
This can be done by enabling the internal Brown-out Detector (BOD) if the operating volt-
age matches the detection level. If not, an external low V
used. If a reset occurs while a write operation is in progress, the write operation will be
completed provided that the power supply voltage is sufficient.
vent the CPU from attempting to decode and execute instructions, effectively protecting
the SPMCSR Register and thus the Flash from unintentional writes.
1. Minimum and maximum programming time is per individual operation.
Table 27-3 on page 297
SPM Programming Time
FHB7
Symbol
7
7
–
CC
FHB6
, the Flash program can be corrupted because the supply voltage is
6
6
–
FHB5
for detailed description and mapping of the Extended Fuse
5
5
–
Min Programming Time
FHB4
4
4
–
3.7 ms
FHB3
3
3
–
ATmega329P/3290P
CC
Table 26-5
FHB2
EFB2
reset protection circuit can be
2
2
Max Programming Time
FHB1
EFB1
1
1
shows the typical pro-
CC
. This will pre-
4.5 ms
FHB0
EFB0
0
0
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