Datasheet

162
8006H–AVR–10/09
ATtiny24/44/84
19.3.1 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, also when the device is
locked.
Signature bytes can also be read by the device firmware. See section “Reading Lock, Fuse and
Signature Data from Software” on page 155.
The three signature bytes reside in a separate address space called the device signature imprint
table. The signature data for ATtiny24/44/84 is given in Table 19-7.
19.3.2 Calibration Byte
The device signature imprint table of ATtiny24/44/84 contains one byte of calibration data for the
internal oscillator, as shown in Table 19-6 on page 161. During reset, this byte is automatically
written into the OSCCAL register to ensure correct frequency of the calibrated oscillator.
Calibration bytes can also be read by the device firmware. See section “Reading Lock, Fuse and
Signature Data from Software” on page 155.
19.4 Page Size
Table 19-7. Device Signature Bytes
Part Signature Byte 0 Signature Byte 1 Signature Byte 0
ATtiny24 0x1E 0x91 0x0B
ATtiny44 0x1E 0x92 0x07
ATtiny84 0x1E 0x93 0x0C
Table 19-8. No. of Words in a Page and No. of Pages in the Flash
Device Flash Size Page Size PCWORD No. of Pages PCPAGE PCMSB
ATt iny2 4
1K words
(2K bytes)
16 words PC[3:0] 64 PC[9:4] 9
ATt iny4 4
2K words
(4K bytes)
32 words PC[4:0] 64 PC[10:5] 10
ATt iny8 4
4K words
(8K bytes)
32 words PC[4:0] 128 PC[11:5] 11
Table 19-9. No. of Words in a Page and No. of Pages in the EEPROM
Device EEPROM Size Page Size PCWORD No. of Pages PCPAGE EEAMSB
ATtiny24 128 bytes 4 bytes EEA[1:0] 32 EEA[6:2] 6
ATtiny44 256 bytes 4 bytes EEA[1:0] 64 EEA[7:2] 7
ATtiny84 512 bytes 4 bytes EEA[1:0] 128 EEA[8:2] 8