ATMEGA328P-20PU Atmel, ATMEGA328P-20PU Datasheet - Page 293

• Manufacturer Part Number: ATMEGA328P-20PU
• Manufacturer: Atmel

Specifications of ATMEGA328P-20PU

• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 20MHz
• Interface Type: SPI/TWI/USART
• Program Memory Type: Flash
• Program Memory Size: 32KB
• Total Internal Ram Size: 2KB
• # I/os (max): 23
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 6-chx10-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Through Hole
• Pin Count: 28
• Package Type: PDIP
• Lead Free Status / Rohs Status: Compliant

27.2.1
27.3
27.4
8025K–AVR–10/09
Signature Bytes
Calibration Byte
Latching of Fuses
Table 27-7.
Note:
The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are locked if
Lock bit1 (LB1) is programmed. Program the Fuse bits before programming the Lock bits.
The fuse values are latched when the device enters programming mode and changes of the
fuse values will have no effect until the part leaves Programming mode. This does not apply to
the EESAVE Fuse which will take effect once it is programmed. The fuses are also latched on
Power-up in Normal mode.
All Atmel microcontrollers have a three-byte signature code which identifies the device. This
code can be read in both serial and parallel mode, also when the device is locked. The three
bytes reside in a separate address space. For the ATmega48P/88P/168P the signature bytes
are given in
Table 27-8.
The ATmega48P/88P/168P has a byte calibration value for the Internal RC Oscillator. This byte
resides in the high byte of address 0x000 in the signature address space. During reset, this byte
is automatically written into the OSCCAL Register to ensure correct frequency of the calibrated
RC Oscillator.
Low Fuse Byte
CKDIV8
CKOUT
SUT1
SUT0
CKSEL3
CKSEL2
CKSEL1
CKSEL0
Part
ATmega48P
ATmega88P
ATmega168P
1. The default value of SUT1..0 results in maximum start-up time for the default clock source.
2. The default setting of CKSEL3..0 results in internal RC Oscillator @ 8 MHz. See
3. The CKOUT Fuse allows the system clock to be output on PORTB0. See
4. See
(3)
(4)
See
page 33
on page 35
Table
Fuse Low Byte
Device ID
Table 8-12 on page 33
”System Clock Prescaler” on page 35
27-8.
for details.
for details.
Bit No
7
6
5
4
3
2
1
0
Signature Bytes Address
0x000
0x1E
0x1E
0x1E
for details.
Description
Divide clock by 8
Clock output
Select start-up time
Select start-up time
Select Clock source
Select Clock source
Select Clock source
Select Clock source
for details.
ATmega48P/88P/168P
0x001
0x92
0x93
0x94
Default Value
0 (programmed)
1 (unprogrammed)
1 (unprogrammed)
0 (programmed)
0 (programmed)
0 (programmed)
1 (unprogrammed)
0 (programmed)
”Clock Output Buffer”
0x002
0x0A
0x0F
0x0B
(1)
(2)
(2)
(2)
Table 8-11 on
(1)
(2)
293