Datasheet

290
2467X–AVR–06/11
ATmega128
Parallel
Programming
Parameters, Pin
Mapping, and
Commands
This section describes how to parallel program and verify Flash Program memory, EEPROM
Data memory, Memory Lock bits, and Fuse bits in the Atmel
®
AVR
®
ATmega128. Pulses are
assumed to be at least 250ns unless otherwise noted.
Signal Names In this section, some pins of the ATmega128 are referenced by signal names describing their
functionality during parallel programming, see Figure 135 and Table 120. 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 122.
When pulsing WR
or OE, the command loaded determines the action executed. The different
Commands are shown in Table 123.
Figure 135. Parallel Programming
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
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