Atmel ATtiny25 User Manual

137
7598H–AVR–07/09
ATtiny25/45/85
21.3 Signature Bytes
All Atmel microcontrollers have a three-byte signature code which identifies the device. This
code can be read in both serial and High-voltage Programming mode, also when the device is
locked. The three bytes reside in a separate address space.
21.3.1 ATtiny25 Signature Bytes
1. 0x000: 0x1E (indicates manufactured by Atmel).
2. 0x001: 0x91 (indicates 2 KB Flash memory).
3. 0x002: 0x08 (indicates ATtiny25 device when 0x001 is 0x91).
21.3.2 ATtiny45 Signature Bytes
1. 0x000: 0x1E (indicates manufactured by Atmel).
2. 0x001: 0x92 (indicates 4 KB Flash memory).
3. 0x002: 0x06 (indicates ATtiny45 device when 0x001 is 0x92).
21.3.3 ATtiny85 Signature Bytes
1. 0x000: 0x1E (indicates manufactured by Atmel).
2. 0x001: 0x93 (indicates 8 KB Flash memory).
3. 0x002: 0x0B (indicates ATtiny85 device when 0x001 is 0x93).
21.4 Calibration Byte
Signature area of the ATtiny25/45/85 has one byte of calibration data for the internal RC Oscilla-
tor. This byte resides in the high byte of address 0x000. During reset, this byte is automatically
written into the OSCCAL Register to ensure correct frequency of the calibrated RC Oscillator.
21.5 Page Size
Table 21-6. No. of Words in a Page and No. of Pages in the Flash
Device Flash Size Page Size PCWORD No. of Pages PCPAGE PCMSB
ATtiny2 5
1K words
(2K bytes)
16 words PC[3:0] 64 PC[9:4] 9
ATtiny4 5
2K words
(4K bytes)
32 words PC[4:0] 64 PC[10:5] 10
ATtiny8 5
4K words
(8K bytes)
32 words PC[4:0] 128 PC[11:5] 11
Table 21-7. No. of Words in a Page and No. of Pages in the EEPROM
Device
EEPROM
Size Page Size PCWORD No. of Pages PCPAGE EEAMSB
ATtiny25 128 bytes 4 bytes EEA[1:0] 32 EEA[6:2] 6
ATtiny45 256 bytes 4 bytes EEA[1:0] 64 EEA[7:2] 7
ATtiny85 512 bytes 4 bytes EEA[1:0] 128 EEA[8:2] 8

Atmel ATtiny25 Specifications

General

Brand	Atmel
Model	ATtiny25
Category	Microcontrollers
Language	English