ATTINY88 Datasheet, PDF (193/246 Pages) ATMEL Corporation – High Endurance Non-volatile Memory Segments

ATtiny88 Automotive
Table 20-5. Fuse Low Byte
Fuse Low Byte
CKDIV8⁽⁴⁾
CKOUT⁽³⁾
Bit No
7
6
SUT1
5
SUT0
4
-
3
-
2
CKSEL1
1
CKSEL0
0
Description
Divide clock by 8
Clock output
Select start-up time
Select start-up time
-
-
Select Clock source
Select Clock source
Default Value
0 (programmed)
1 (unprogrammed)
1 (unprogrammed)⁽¹⁾
0 (programmed)⁽¹⁾
1 (unprogrammed)⁽²⁾
1 (unprogrammed)⁽²⁾
1 (unprogrammed)⁽²⁾
0 (programmed)⁽²⁾
Note: 1. The default value of SUT1..0 results in maximum start-up time for the default clock source.
See Table 6-4 on page 29 for details.
2. The default setting of CKSEL1..0 results in internal oscillator @ 8 MHz. See Table 6-3 on page
29 for details.
3. The CKOUT Fuse allows the system clock to be output on PORTB0. See “Clock Output Buffer”
on page 31 for details.
4. See “System Clock Prescaler” on page 31 for details.
The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are locked if
Lock bit1 (LB1) is programmed. Program the Fuse bits before programming the Lock bits.
20.2.1
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.
20.3
Signature Bytes
All Atmel microcontrollers have a three-byte signature code which identifies the device. This
code can be read in both serial and parallel mode, also when the device is locked. The three
bytes reside in a separate address space. For the ATtiny88 the signature bytes are given in
Table 20-6.
Table 20-6. Device ID
Part
ATtiny88
Signature Bytes Address
0x000
0x001
0x1E
0x93
0x002
0x11
20.4
Calibration Byte
The ATtiny88 has a byte calibration value for the internal oscillator. This byte resides in the high
byte of address 0x000 in the signature address space. During reset, this byte is automatically
written into the OSCCAL Register to ensure correct frequency of the calibrated oscillator.
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