Datasheet

290
2545T–AVR–05/11
ATmega48/88/168
Figure 28-1. Parallel programming.
Note: V
CC
- 0.3V < AV
CC
< V
CC
+ 0.3V, however, AV
CC
should always be within 4.5V - 5.5V.
Table 28-11. 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
PAG EL P D7 I
Program memory and EEPROM data page
load
BS2 PC2 I
Byte select 2 (“0” selects Low byte, “1” selects
2’nd high byte)
DATA {PC[1:0]: PB[5:0]} I/O Bi-directional data bus (output when OE is low)
Table 28-12. 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
GND
XTAL1
PD1
PD2
PD3
PD4
PD5
PD6
PC[1:0]:PB[5:0]
DATA
RESET
PD7
+12V
BS1
XA0
XA1
OE
RDY/BSY
PAGEL
PC2
WR
BS2
AVCC
+4.5V - 5.5V
+4.5V - 5.5V