ATmega325PA Atmel Corporation, ATmega325PA Datasheet - Page 288

• Manufacturer Part Number: ATmega325PA
• Manufacturer: Atmel Corporation

8285D–AVR–06/11
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P
Table 27-9.
Table 27-10. Pin Values Used to Enter Programming Mode
Table 27-11. XA1 and XA0 Coding
Table 27-12. Command Byte Bit Coding
Programming Mode
Signal Name in
XA1
Command Byte
0
0
1
1
1000 0000
0100 0000
0010 0000
0001 0000
0001 0001
0000 1000
0000 0100
0000 0010
0000 0011
PAGEL
DATA
BS2
PAGEL
XA1
XA0
BS1
Pin
Pin Name Mapping
XA0
0
1
0
1
Pin Name
PB7-0
Command Executed
Chip Erase
Write Fuse bits
Write Lock bits
Write Flash
Write EEPROM
Read Signature Bytes and Calibration byte
Read Fuse and Lock bits
Read Flash
Read EEPROM
Action when XTAL1 is Pulsed
Load Flash or EEPROM Address (High or low address byte determined by
BS1).
Load Data (High or Low data byte for Flash determined by BS1).
Load Command
No Action, Idle
PD7
PA0
I/O
I/O
I
I
Prog_enable[3]
Prog_enable[2]
Prog_enable[1]
Prog_enable[0]
Function
Program Memory and EEPROM data Page Load
Byte Select 2 (“0” selects low byte, “1” selects 2
byte)
Bi-directional Data bus (Output when OE is low).
Symbol
Value
0
0
0
0
nd
high
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