atmega103 ATMEL Corporation, atmega103 Datasheet - Page 110

• Manufacturer Part Number: atmega103
• Description: Atmega103 8-bit With 128k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Reading the Flash
Reading the EEPROM
Programming the Fuse Bits
110
ATmega103(L)
Figure 75. Programming the EEPROM Waveforms
The algorithm for reading the Flash memory is as follows (refer to “Programming the
Flash” on page 107 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
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 107 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
5. Set OE to “1”.
The algorithm for programming the Fuse bits is as follows (refer to “Programming the
Flash” on page 107 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.
RDY/BSY
RESET
PAGEL
XTAL1
DATA
DATA.
DATA.
Bit 5 = SPIEN Fuse bit
Bit 3 = EESAVE Fuse bit
Bit 2 = always “1”
XA1
XA2
BS1
BS2
WR
OE
+12V
$11
ADDR. HIGH
ADDR. LOW
DATA LOW
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