ATMEGA328P-20PU Atmel, ATMEGA328P-20PU Datasheet - Page 303

• 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

27.7.14
27.7.15
27.8
8025K–AVR–10/09
Serial Downloading
Reading the Calibration Byte
Parallel Programming Characteristics
The algorithm for reading the Calibration byte is as follows (refer to
page 297
1. A: Load Command “0000 1000”.
2. B: Load Address Low Byte, 0x00.
3. Set OE to “0”, and BS1 to “1”. The Calibration byte can now be read at DATA.
4. Set OE to “1”.
For chracteristics of the Parallel Programming, see
page
Both the Flash and EEPROM memory arrays can be programmed using the serial SPI bus while
RESET is pulled to GND. The serial interface consists of pins SCK, MOSI (input) and MISO (out-
put). After RESET is set low, the Programming Enable instruction needs to be executed first
before program/erase operations can be executed. NOTE, in
mapping for SPI programming is listed. Not all parts use the SPI pins dedicated for the internal
SPI interface.
Figure 27-7. Serial Programming and Verify
Notes:
When programming the EEPROM, an auto-erase cycle is built into the self-timed programming
operation (in the Serial mode ONLY) and there is no need to first execute the Chip Erase
instruction. The Chip Erase operation turns the content of every memory location in both the
Program and EEPROM arrays into 0xFF.
Depending on CKSEL Fuses, a valid clock must be present. The minimum low and high periods
for the serial clock (SCK) input are defined as follows:
Low: > 2 CPU clock cycles for f
High: > 2 CPU clock cycles for f
319.
1. If the device is clocked by the internal Oscillator, it is no need to connect a clock source to the
2. V
for details on Command and Address loading):
XTAL1 pin.
CC
- 0.3V <
AV
CC
< V
MOSI
MISO
SCK
ck
ck
CC
< 12 MHz, 3 CPU clock cycles for f
< 12 MHz, 3 CPU clock cycles for f
+ 0.3V, however,
XTAL1
RESET
GND
(1)
AV
”Parallel Programming Characteristics” on
CC
AVCC
ATmega48P/88P/168P
VCC
should always be within 1.8 - 5.5V
+1.8 - 5.5V
+1.8 - 5.5V
Table 27-15 on page
(2)
”Programming the Flash” on
ck
ck
>= 12 MHz
>= 12 MHz
304, the pin
303