
277
ATmega64A [DATASHEET]
8160D–AVR–02/2013
1.
0x000: 0x1E (indicates manufactured by Atmel)
2.
0x001: 0x96 (indicates 64 Kbyte Flash memory)
3.
0x002: 0x02 (indicates ATmega64A device when 0x001 is 0x96)
28.4
Calibration Byte
The ATmega64A stores four different calibration values for the internal RC Oscillator. These bytes resides in the
signature row high byte of the addresses 0x000, 0x0001, 0x0002, and 0x0003 for 1, 2, 4, and 8 MHz respectively.
During Reset, the 1 MHz value is automatically loaded into the OSCCAL Register. If other frequencies are used,
details.
28.5
Parallel Programming Parameters, Pin Mapping, and Commands
This section describes how to parallel program and verify Flash Program memory, EEPROM Data memory, Mem-
ory Lock bits, and Fuse bits in the ATmega64A. Pulses are assumed to be at least 250 ns unless otherwise noted.
28.5.1
Signal Names
In this section, some pins of the ATmega64A are referenced by signal names describing their functionality during
parallel programming, see
Figure 28-1 and
Table 28-6. 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
When pulsing WR or OE, the command loaded determines the action executed. The different Commands are
Figure 28-1. Parallel Programming
Table 28-6.
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)
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