atmega103 ATMEL Corporation, atmega103 Datasheet - Page 109

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

Programming the EEPROM
0945I–AVR–02/07
Figure 74. Programming the Flash Waveforms (Continued)
The programming algorithm for the EEPROM data memory is as follows (refer to “Pro-
gramming the Flash” on page 107 for details on command, address and data loading):
1. A: Load Command “0001 0001”.
2. H: Load Address High Byte ($00 - $0F).
3. B: Load Address Low Byte ($00 - $FF).
4. E: Load Data Low Byte ($00 - $FF).
L: Write Data Low Byte.
1. Set BS to “0”. This selects low data.
2. Give WR a negative pulse. This starts programming of the data byte. RDY/BSY
3. Wait until RDY/BSY goes high to program the next byte.
(See Figure 75 for signal waveforms.)
The loaded command and address are retained in the device during programming. For
efficient programming, the following should be considered:
•
•
•
These considerations also apply to Flash, EEPROM and signature bytes reading.
goes low.
The command needs only be loaded once when writing or reading multiple memory
locations.
Address High Byte needs only be loaded before programming a new 256-word page
in the EEPROM.
Skip writing the data value $FF that is the contents of the entire EEPROM after a
chip erase.
RDY/BSY
RESET
PAGEL
XTAL1
DATA
XA1
XA0
BS1
BS2
WR
OE
+12V
DATA HIGH
ATmega103(L)
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