289
4317I–AVR–01/08
AT90PWM2/3/2B/3B
25.8.5
Programming the EEPROM
The EEPROM is organized in pages, see
. When programming the
EEPROM, the program 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
“Programming the Flash” on page 287
for details on Command, Address and
Data loading):
1.
A: Load Command “0001 0001”.
2.
G: Load Address High Byte (0x00 - 0xFF).
3.
B: Load Address Low Byte (0x00 - 0xFF).
4.
C: Load Data (0x00 - 0xFF).
5.
E: Latch data (give PAGEL a positive pulse).
K: Repeat 3 through 5 until the entire buffer is filled.
L: Program EEPROM page
1.
Set BS1 to “0”.
2.
Give WR a negative pulse. This starts programming of the EEPROM page. RDY/BSY
goes low.
3.
Wait until to RDY/BSY goes high before programming the next page (See
signal waveforms).
Figure 25-4. Programming the EEPROM Waveforms
25.8.6
Reading the Flash
The algorithm for reading the Flash memory is as follows (refer to
for details on Command and Address loading):
1.
A: Load Command “0000 0010”.
2.
G: Load Address High Byte (0x00 - 0xFF).
3.
B: Load Address Low Byte (0x00 - 0xFF).
4.
Set OE to “0”, and BS1 to “0”. The Flash word low byte can now be read at DATA.
5.
Set BS1 to “1”. The Flash word high byte can now be read at DATA.
6.
Set OE to “1”.
RDY/BSY
WR
OE
RESET +12V
PAGEL
BS2
0x11
ADDR. HIGH
DATA
ADDR. LOW
DATA
ADDR. LOW
DATA
XX
XA1
XA0
BS1
XTAL1
XX
A
G
B
C
E
B
C
E
L
K