Datasheet

159
8024A–AVR–04/08
ATmega8HVA/16HVA
Figure 27-5. High-voltage Serial Programming Waveforms
27.8.5 Programming the EEPROM
The EEPROM is organized in pages, see ”High-voltage Serial Programming” on page 173.
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
memory is as follows (refer to Table 27-14 on page 160):
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
The algorithm for reading the Flash memory is as follows (refer to Table 27-14 on page 160):
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
The algorithm for reading the EEPROM memory is as follows (refer to Table 27-14 on page
160):
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
Table 27-14 on page 160.
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 on
page 160.
27.8.10 Power-off sequence
Exit Programming mode by powering the device down, or by bringing RESET pin to 0V.
MSB
MSB
MSB LSB
LSB
LSB
012345678910
SDI
SII
SDO
SCI