atmega323l ATMEL Corporation, atmega323l Datasheet - Page 199

• Manufacturer Part Number: atmega323l
• Description: Atmega323 8-bit Avr Microcontroller With 32k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Programming Times for Non-
volatile Memory
1457G–AVR–09/03
The internal RC Oscillator is used to control programming time when programming or
erasing Flash, EEPORM, Fuses and Lock bits. During Parallel or Serial Programming,
the device is in reset, and this Oscillator runs at its initial, uncalibrated frequency, which
may vary from 0.5 MHz to 1.0 MHz. In software it is possible to calibrate this Oscillator to
1.0 MHz (see “Calibrated Internal RC Oscillator” on page 41). Consequently, program-
ming times will be shorter and more accurate when programming or erasing non-volatile
memory from software, using SPM or the EEPROM interface. See Table 68 for a sum-
mary of programming times.
Table 68. Maximum Programming Times for Non-volatile Memory
Notes:
Figure 99. Serial Programming Waveforms
Operation
Chip Erase
Flash Write
EEPROM
Write
Fuse/Lock
bit write
SERIAL DATA OUTPUT
SERIAL CLOCK INPUT
SERIAL DATA INPUT
(2)
1. Includes variation over voltage and temperature after RC Oscillator has been cali-
2. Parallel EEPROM programming takes 1K cycles
PB5 (MOSI)
PB6 (MISO)
brated to 1.0 MHz
PB7(SCK)
SAMPLE
Symbol
t
t
t
t
WD_CE
WD_FLASH
WD_EEPROM
WD_FUSE
MSB
MSB
RC Oscillator
Number of
Cycles
16K
8K
2K
1K
32 ms
16 ms
4 ms
2 ms
2.7V
Parallel/Serial
Programming
ATmega323(L)
3.8 ms
1.9 ms
30 ms
15 ms
5.0V
programming
8.5 ms
2.2 ms
1.1 ms
LSB
LSB
17 ms
Self-
(1)
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