Datasheet

295
2490R–AVR–02/2013
ATmega64(L)
Table 120. 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 121. 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
Table 122. XA1 and XA0 Coding
XA1 XA0 Action when XTAL1 is Pulsed
0 0 Load Flash or EEPROM Address (High or low address byte determined by BS1)
0 1 Load Data (High or Low data byte for Flash determined by BS1)
1 0 Load Command
1 1 No Action, Idle