339
7679H–CAN–08/08
AT90CAN32/64/128
25.3
Signature Bytes
All Atmel microcontrollers have a three-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.
25.4
Calibration Byte
The AT90CAN32/64/128 has a 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 calibrated
RC Oscillator.
25.5
Parallel Programming Overview
This section describes how to parallel program and verify Flash Program memory, EEPROM
Data memory, Memory Lock bits, and Fuse bits in the AT90CAN32/64/128. Pulses are assumed
to be at least 250 ns unless otherwise noted.
25.5.1
Signal Names
In this section, some pins of the AT90CAN32/64/128 are referenced by signal names describing
their functionality during parallel programming, see
. 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
When pulsing WR or OE, the command loaded determines the action executed. The different
Commands are shown in
.
Table 25-6.
Signature Bytes
Device
Address
Value
Signature Byte Description
AT90CAN32
0
0x1E
Indicates manufactured by Atmel
1
0x95
Indicates 32 KB Flash memory
2
0x81
Indicates AT90CAN32 device when address 1 contains 0x95
AT90CAN64
0
0x1E
Indicates manufactured by Atmel
1
0x96
Indicates 64 KB Flash memory
2
0x81
Indicates AT90CAN64 device when address 1 contains 0x96
AT90CAN128
0
0x1E
Indicates manufactured by Atmel
1
0x97
Indicates 128 KB Flash memory
2
0x81
Indicates AT90CAN128 device when address 1 contains 0x97