Datasheet

263
ATmega325/3250/645/6450
2570K–AVR–04/07
Figure 112. Parallel Programming
Table 112. Pin Name Mapping
Signal Name in
Programming Mode Pin Name I/O Function
RDY/BSY PD1 O
0: Device is busy programming, 1: Device is ready
for new command.
OE PD2 I Output Enable (Active low).
WR
PD3 I Write Pulse (Active low).
BS1 PD4 I
Byte Select 1 (“0” selects low byte, “1” selects
high byte).
XA0 PD5 I XTAL Action Bit 0
XA1 PD6 I XTAL Action Bit 1
PAGEL PD7 I Program Memory and EEPROM data Page Load.
BS2 PA0 I
Byte Select 2 (“0” selects low byte, “1” selects
2’nd high byte).
DATA PB7-0 I/O Bi-directional Data bus (Output when OE is low).
Table 113. Pin Values Used to Enter Programming Mode
Pin Symbol Value
PAGEL Prog_enable[3] 0
XA1 Prog_enable[2] 0
XA0 Prog_enable[1] 0
BS1 Prog_enable[0] 0
VCC
+5V
GND
XTAL1
PD1
PD2
PD3
PD4
PD5
PD6
PB7 - PB0 DATA
RESET
PD7
+12 V
BS1
XA0
XA1
OE
RDY/BSY
PAGEL
PA0
WR
BS2
AVCC
+5V