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ATmega162/V
Latching of Fuses
The Fuse values are latched when the device enters Programming mode and changes of the
Fuse values will have no effect until the part leaves Programming mode. This does not apply to
the EESAVE Fuse which will take effect once it is programmed. The Fuses are also latched on
Power-up in Normal mode.
Signature Bytes
All Atmel microcontrollers have a 3-byte signature code which identifies the device. This code
can be read in both Serial and Parallel mode, also when the device is locked. The three bytes
reside in a separate address space.
For the ATmega162 the signature bytes are:
1.
0x000: 0x1E (indicates manufactured by Atmel).
2.
0x001: 0x94 (indicates 16KB Flash memory).
3.
0x002: 0x04 (indicates ATmega162 device when 0x001 is 0x94).
Calibration Byte
The ATmega162 has a one-byte calibration value for the internal RC Oscillator. This byte
resides in the high byte of address 0x000 in the signature address space. During Reset, this
byte is automatically written into the OSCCAL Register to ensure correct frequency of the cali-
brated RC Oscillator.
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 ATmega162. Pulses are assumed to be at
least 250 ns unless otherwise noted.
Signal Names
In this section, some pins of the ATmega162 are referenced by signal names describing their
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.
When pulsing WR or OE, the command loaded determines the action executed. The different
Figure 96. Parallel Programming
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