ATMEGA329P-20MN Atmel, ATMEGA329P-20MN Datasheet - Page 24

IC MCU AVR 32K 20MHZ 64QFN

ATMEGA329P-20MN

Manufacturer Part Number
ATMEGA329P-20MN
Description
IC MCU AVR 32K 20MHZ 64QFN
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA329P-20MN

Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
SPI, UART/USART, USI
Peripherals
Brown-out Detect/Reset, LCD, POR, PWM, WDT
Number Of I /o
54
Program Memory Size
32KB (16K x 16)
Program Memory Type
FLASH
Eeprom Size
1K x 8
Ram Size
2K x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
64-MLF®, 64-QFN
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
8021G–AVR–03/11
• Bit 0 – EERE: EEPROM Read Enable
The EEPROM Read Enable Signal EERE is the read strobe to the EEPROM. When the correct
address is set up in the EEAR Register, the EERE bit must be written to a logic one to trigger the
EEPROM read. The EEPROM read access takes one instruction, and the requested data is
available immediately. When the EEPROM is read, the CPU is halted for four cycles before the
next instruction is executed.
The user should poll the EEWE bit before starting the read operation. If a write operation is in
progress, it is neither possible to read the EEPROM, nor to change the EEAR Register.
The calibrated Oscillator is used to time the EEPROM accesses.
gramming time for EEPROM access from the CPU.
Table 7-1.
The following code examples show one assembly and one C function for writing to the
EEPROM. The examples assume that interrupts are controlled (e.g. by disabling interrupts glob-
ally) so that no interrupts will occur during execution of these functions. The examples also
assume that no Flash Boot Loader is present in the software. If such code is present, the
EEPROM write function must also wait for any ongoing SPM command to finish.
Symbol
EEPROM write (from CPU)
EEPROM Programming Time
Number of Calibrated
RC Oscillator Cycles
27,072
ATmega329P/3290P
Table 7-1
Typical Programming Time
lists the typical pro-
3.4ms
24

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