Datasheet

300
8021G–AVR–03/11
ATmega329P/3290P
27.6.1 Signal Names
In this section, some pins of the ATmega329P/3290P are referenced by signal names describ-
ing their functionality during parallel programming, see Figure 27-1 and Table 27-9. Pins not
described in the following table are referenced by pin names.
The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a positive pulse.
The bit coding is shown in Table 27-11.
When pulsing WR
or OE, the command loaded determines the action executed. The different
Commands are shown in Table 27-12.
Figure 27-1. Parallel Programming
Table 27-9. 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).
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