Datasheet

241
ATtiny828 [DATASHEET]
8371A–AVR–08/12
Figure 98. Mapping Between BS1, BS2 and the Fuse and Lock Bits During Read
23.2.13 Reading Signature Bytes
The algorithm for reading the signature bytes is as follows (see “Programming the Flash” on page 235 for details on
command and address loading):
1. A: Load command “0000 1000”
2. B: Load address low byte (0x00 – 0x02)
3. Set OE
to “0”, and BS1 to “0”. The selected signature byte can now be read at DATA.
4. Set OE
to “1”.
23.2.14 Reading the Calibration Byte
The algorithm for reading the calibration byte is as follows (see “Programming the Flash” on page 235 for details on
command and address loading):
1. A: Load command “0000 1000”.
2. B: Load address low byte, 0x00.
3. Set OE
to “0”, and BS1 to “1”. The calibration byte can now be read at DATA.
4. Set OE
to “1”.
23.3 Serial Programming
Flash and EEPROM memory arrays can both be programmed using the serial SPI bus while RESET is pulled to GND.
The serial interface consists of pins SCK, MOSI (input) and MISO (output). After RESET
is set low, the Programming
Enable instruction needs to be executed before program/erase operations can be executed.
Serial programming signals and connections are illustrated in Figure 99, below. The pin mapping is listed in Table 100 on
page 243.
Lock Bits
0
1
BS2
Fuse High Byte
0
1
BS1
DATA
Fuse Low Byte
0
1
BS2
Extended Fuse Byte