
109
1477K–AVR–08/10
ATtiny26(L)
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 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.
For the ATtiny26 the signature bytes are:
1. $000: $1E (indicates manufactured by Atmel).
2. $001: $91 (indicates 2KB Flash memory).
3. $002: $09 (indicates ATtiny26 device when $001 is $91).
Calibration Byte
The ATtiny26 stores four different calibration values for the internal RC Oscillator. These bytes
resides in the signature row high byte of the addresses 0x0000, 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, the calibration value has to be loaded manu-
Page Size
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 ATtiny26. Pulses are assumed to be at
least 250 ns unless otherwise noted.
Signal Names
In this section, some pins of the ATtiny26 are referenced by signal names describing their func-
tionality during parallel programming, see
Figure 58 and
Table 54. 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.
When pulsing WR or OE, the command loaded determines the action executed. The different
Table 52. No. of Words in a Page and no. of Pages in the Flash
Flash Size
Page Size
PCWORD
No. of Pages
PCPAGE
PCMSB
1K words (2K bytes)
16 words
PC[3:0]
64
PC[9:4]
9
Table 53. No. of Words in a Page and no. of Pages in the EEPROM
EEPROM Size
Page Size
PCWORD
No. of Pages
PCPAGE
EEAMSB
128 bytes
4 bytes
EEA[1:0]
32
EEA[7:0]
7