ATmega16M1 datasheet(25/365 Pages) ATMEL

номер детали	ATmega16M1

подробное описание детали	8-bit Microcontroller with 16K/32K/64K Bytes In-System Programmable Flash

PDF	365 Pages

Scroll/Zoom	100%

производитель	ATMEL [ATMEL Corporation]

домашняя страница	http://www.atmel.com

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7647F–AVR–04/09

ATmega16/32/64/M1/C1

• 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. Table 4-2 lists the typical pro-

gramming time for EEPROM access from the CPU.

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.

Table 4-2.

EEPROM Programming Time.

Symbol

Number of Calibrated RC Oscillator Cycles

Typ Programming Time

EEPROM write

(from CPU)

26368

3.3 ms

ATmega16M1 датащи(PDF) 25 Page - ATMEL Corporation