ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 165

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

21.2.1
21.3
21.4
7701E–AVR–02/11
Signature Bytes
Calibration Byte
Latching of Fuses
Table 21-5.
Notes:
The status of the fuse bits is not affected by chip erase. Note that the fuse bits are locked if
lock bit 1 (LB1) is programmed. Program the fuse bits before programming the lock bits.
The fuse values are latched when the device enters programming mode, and changes in 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.
All Atmel
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 Atmel ATtiny24/44/84, the
signature bytes are given in
Table 21-6.
The signature area of the Atmel ATtiny24/44/84 has one byte of calibration data for the inter-
nal RC oscillator. This byte resides in the high byte of address 0x000. During reset, this byte is
automatically written into the OSCCAL register to ensure the correct frequency of the cali-
brated RC oscillator.
Fuse Low Byte
CKDIV8
CKOUT
SUT1
SUT0
CKSEL3
CKSEL2
CKSEL1
CKSEL0
Device
ATtiny24
ATtiny44
ATtiny84
1. See
2. The default value of SUT1..0 results in maximum start-up time for the default clock source.
3. The default setting of CKSEL3..0 results in internal RC Oscillator @ 8.0 MHz. See
(1)
®
microcontrollers have a three-byte signature code that identifies the device. This
See
on page 29
Fuse Low Byte
Device ID
“System Clock Prescaler” on page 31
Table 7-7 on page 29
for details.
Bit No
Atmel ATtiny24/44/84 [Preliminary]
Table
7
6
5
4
3
2
1
0
0x000
0x1E
0x1E
0x1E
21-6.
for details.
Description
Divide clock by 8
Clock Output Enable
Select start-up time
Select start-up time
Select Clock source
Select Clock source
Select Clock source
Select Clock source
Signature Bytes Address
for details.
0x001
0x91
0x92
0x93
1 (unprogrammed)
0 (programmed)
0 (programmed)
0 (programmed)
0 (programmed)
Default Value
0 (programmed)
1 (unprogrammed)
1 (unprogrammed)
0x002
0x0C
0x0B
0x07
(2)
(3)
(3)
(3)
(2)
(3)
Table 7-6
165