ATMEGA325-16AJ ATMEL [ATMEL Corporation], ATMEGA325-16AJ Datasheet - Page 270

• Manufacturer Part Number: ATMEGA325-16AJ
• Description: 8-bit Microcontroller with In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

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ATmega325/3250/645/6450
Table 119. Parallel Programming Characteristics, V
Notes:
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 (output). After RESET is set low, the Programming Enable instruction
needs to be executed first before program/erase operations can be executed. NOTE, in
Table 118 on page 261, the pin mapping for SPI programming is listed. Not all parts use
the SPI pins dedicated for the internal SPI interface.
Figure 120. Serial Programming and Verify
Notes:
When programming the EEPROM, an auto-erase cycle is built into the self-timed pro-
gramming 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
Symbol
t
t
t
BVDV
OLDV
OHDZ
1.
2. t
1. If the device is clocked by the internal Oscillator, it is no need to connect a clock
2. V
bits commands.
source to the XTAL1 pin.
t
WLRH_CE
WLRH
CC
Parameter
BS1 Valid to DATA valid
OE Low to DATA Valid
OE High to DATA Tri-stated
- 0.3V < AVCC < V
is valid for the Write Flash, Write EEPROM, Write Fuse bits and Write Lock
is valid for the Chip Erase command.
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, AVCC should always be within 1.8 - 5.5V
XTAL1
RESET
GND
(1)
AVCC
VCC
CC
= 5V ± 10% (Continued)
+1.8 - 5.5V
+1.8 - 5.5V
Min
0
(2)
Typ
ck
ck
>= 12 MHz
>= 12 MHz
Max
250
250
250
2570A–AVR–09/04
Units
ns
ns
ns