Atmel AVR ATmega103 Manual page 105

Reading the Flash
Reading the EEPROM
Programming the Fuse Bits
0945G–09/01
Figure 75. Programming the EEPROM Waveforms
DATA $11
XA1
XA2
BS1
XTAL1
WR
RDY/BSY
+12V
RESET
OE
BS2
PAGEL
The algorithm for reading the Flash memory is as follows (refer to "Programming the
Flash" on page 102 for details on command and address loading):
1. A: Load Command "0000 0010".
2. H: Load Address High Byte ($00 - $FF).
3. B: Load Address Low Byte ($00 - $FF).
4. Set OE to "0", and BS1 to "0". The Flash word low byte can now be read at
DATA.
5. Set BS to "1". The Flash word high byte can now be read at DATA.
6. Set OE to "1".
The algorithm for reading the EEPROM memory is as follows (refer to "Programming the
Flash" on page 102 for details on command and address loading):
1. A: Load Command "0000 0011".
2. H: Load Address High Byte ($00 - $0F).
3. B: Load Address ($00 - $FF).
4. Set OE to "0", and BS1 to "0". The EEPROM data byte can now be read at
DATA.
5. Set OE to "1".
The algorithm for programming the Fuse bits is as follows (refer to "Programming the
Flash" on page 102 for details on command and data loading):
1. A: Load Command "0100 0000".
2. C: Load Data Low Byte. Bit n = "0" programs and bit n = "1" erases the Fuse bit.
Bit 5 = SPIEN Fuse bit
Bit 3 = EESAVE Fuse bit
Bit 2 = always "1"
ADDR. HIGH ADDR. LOW DATA LOW
ATmega103(L)
105