Rainbow Electronics ATmega162V - Manual (Page 233)

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ATmega162/V
2513E–AVR–09/03
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 fre-
quency of the calibrated 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 functionality during parallel programming, see Figure 96 and Table 102. 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 posi-
tive pulse. The bit coding is shown in Table 104.
When pulsing WR or OE, the command loaded determines the action executed. The dif-
ferent Commands are shown in Table 105.
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