Datasheet

228
ATtiny828 [DATASHEET]
8371A–AVR–08/12
3. This setting selects Calibrated Internal 8MHz Oscillator.
Fuse bits are locked when Lock Bit 1 (LB1) is programmed. Hence, fuse bits must be programmed before lock bits.
Fuse bits are not affected by a Chip Erase.
22.2.1 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.
22.3 Device Signature Imprint Table
The device signature imprint table is a dedicated memory area used for storing miscellaneous device information, such
as the device signature and oscillator calibaration data. Most of this memory segment is reserved for internal use, as
outlined in Table 92.
Byte addresses are used when the device itself reads the data with the LPM command. External programming devices
must use word addresses.
Table 92. Contents of Device Signature Imprint Table
Notes: 1. For more information, see section “Signature Bytes” below.
2. For more information, see section “Calibration Bytes” below.
3. See “Temperature Measurement” on page 148. Calibration data is valid for ATtiny828R-devices, only.
4. Unsigned, fixed point, two’s complement: [0:(255/128)].
5. Signed integer, two’s complement: [-127:+128].
Word Address
(External)
Byte Address
(Internal)
Description
0x00
0x00 Signature byte 0
(1)
0x01 Calibration data for internal 8MHz oscillator (OSCCAL0)
(2)
0x01
0x02 Signature byte 1
(1)
0x03 Oscillator temperature calibration data (OSCTCAL0A)
0x02
0x04 Signature byte 2
(1)
0x05 Oscillator temperature calibration data (OSCTCAL0B)
0x03
0x06 Reserved
0x07 Calibration data for internal 32kHz oscillator (OSCCAL1)
(2)
0x04 ...0x15
... Reserved
... Reserved
0x16
0x2C Calibration data for temperature sensor (gain)
(3)(4)
0x2D Calibration data for temperature sensor (offset)
(3)(5)
0x17...0x3F
... Reserved
... Reserved