
159
8024A–AVR–04/08
ATmega8HVA/16HVA
Figure 27-5. High-voltage Serial Programming Waveforms
27.8.5
Programming the EEPROM
When programming the EEPROM, the data is latched into a page buffer. This allows one page
of data to be programmed simultaneously. The programming algorithm for the EEPROM Data
1.
Load Command “Write EEPROM”.
2.
Load EEPROM Page Buffer.
3.
Program EEPROM Page. Wait after Instr. 2 until SDO goes high for the “Page Program-
ming” cycle to finish.
4.
Repeat 2 through 3 until the entire EEPROM is programmed or until all data has been
programmed.
5.
End Page Programming by Loading Command “No Operation”.
27.8.6
Reading the Flash
1.
Load Command "Read Flash".
2.
Read Flash Low and High Bytes. The contents at the selected address are available at
serial output SDO.
27.8.7
Reading the EEPROM
1.
Load Command “Read EEPROM”.
2.
Read EEPROM Byte. The contents at the selected address are available at serial output
SDO.
27.8.8
Programming and Reading the Fuse and Lock Bits
The algorithms for programming and reading the Fuse Low/High bits and Lock bits are shown in
27.8.9
Reading the Signature Bytes and Calibration Byte
The algorithms for reading the Signature bytes and Calibration byte are shown in
Table 27-14 on27.8.10
Power-off sequence
Exit Programming mode by powering the device down, or by bringing RESET pin to 0V.
MSB
LSB
0123456789
10
SDI
SII
SDO
SCI