A000046 Arduino, A000046 Datasheet - Page 272

• Manufacturer Part Number: A000046
• Description: MCU, MPU & DSP Development Tools Uno
• Manufacturer: Arduino
• Series: -r
• Type: MCUr

Specifications of A000046

• Processor To Be Evaluated: ATmega328
• Interface Type: USB, I2C, SPI
• Dimensions: 2.7 in x 2.1 in
• Operating Supply Voltage: 5 V
• Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: ATmega328

25.2.3
25.2.4
8161D–AVR–10/09
Preventing Flash Corruption
Programming Time for Flash when Using SPM
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. Keep the AVR RESET active (low) during periods of insufficient power supply voltage.
2. 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 25-1.
Note:
Flash write (Page Erase, Page Write, and
write Lock bits by SPM)
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.
SPM Programming Time
Symbol
CC
, the Flash program can be corrupted because the supply voltage is
ATmega48PA/88PA/168PA/328P
(1)
Min Programming Time
3.7 ms
CC
Table 26-6
reset protection circuit can be
Max Programming Time
shows the typical pro-
CC
. This will pre-
4.5 ms
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