105
8126F–AVR–05/12
ATtiny13A
Note that fuse bits are locked if Lock Bit 1 (LB1) is programmed. Program the fuse bits before
programming the lock bits. The status of the fuse bits is not affected by Chip Erase.
Fuse bits can also be read by the device firmware. See section
17.2.1
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.
17.3
Calibration Bytes
The signature area of the ATtiny13A contains two bytes of calibration data for the internal oscil-
lator. The calibration data in the high byte of address 0x00 is for use with the oscillator set to 9.6
MHz operation. During reset, this byte is automatically written into the OSCCAL register to
ensure correct frequency of the oscillator.
There is a separate calibration byte for the internal oscillator in 4.8 MHz mode of operation but
this data is not loaded automatically. The hardware always loads the 9.6 MHz calibration data
during reset. To use separate calibration data for the oscillator in 4.8 MHz mode the OSCCAL
register must be updated by firmware. The calibration data for 4.8 MHz operation is located in
the high byte at address 0x01 of the signature area.
17.4
Signature Bytes
All Atmel microcontrollers have a three-byte signature code which identifies the device. This
code can be read in both serial and high-voltage programming mode, even when the device is
locked. The three bytes reside in a separate address space.
For the ATtiny13A the signature bytes are:
• 0x000: 0x1E (indicates manufactured by Atmel).
• 0x001: 0x90 (indicates 1 KB Flash memory).
• 0x002: 0x07 (indicates ATtiny13A device when 0x001 is 0x90).
17.5
Page Size
Table 17-5.
No. of Words in a Page and No. of Pages in the Flash
Flash Size
Page Size
PCWORD
No. of Pages
PCPAGE
PCMSB
512 words (1K byte)
16 words
PC[3:0]
32
PC[8:4]
8
Table 17-6.
No. of Words in a Page and No. of Pages in the EEPROM
EEPROM Size
Page Size
PCWORD
No. of Pages
PCPAGE
EEAMSB
64 bytes
4 bytes
EEA[1:0]
16
EEA[5:2]
5