Datasheet

161
8183F–AVR–06/12
ATtiny24A/44A/84A
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 154.
The three signature bytes reside in a separate address space called the device signature imprint
table. The signature data for ATtiny24A/44A/84A is given in Table 19-7.
19.3.2 Calibration Byte
The device signature imprint table of ATtiny24A/44A/84A contains one byte of calibration data
for the internal oscillator, as shown in Table 19-6 on page 160. During reset, this byte is auto-
matically 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 154.
19.4 Page Size
Table 19-7. Device Signature Bytes
Part Signature Byte 0 Signature Byte 1 Signature Byte 0
ATtiny24A 0x1E 0x91 0x0B
ATtiny44A 0x1E 0x92 0x07
ATtiny84A 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
ATtiny24A
1K word
(2K bytes)
16 words PC[3:0] 64 PC[9:4] 9
ATtiny44A
2K words
(4K bytes)
32 words PC[4:0] 64 PC[10:5] 10
ATtiny84A
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
ATtiny24A 128 bytes 4 bytes EEA[1:0] 32 EEA[6:2] 6
ATtiny44A 256 bytes 4 bytes EEA[1:0] 64 EEA[7:2] 7
ATtiny84A 512 bytes 4 bytes EEA[1:0] 128 EEA[8:2] 8