AT90S/LS2333 and AT90S/LS4433
75
• Address high byte needs only be loaded before programming a new 256 word page in the Flash.
• Skip writing the data value $FF, that is the contents of the entire Flash and EEPROM after a Chip Erase.
These considerations also applies to EEPROM programming, and Flash, EEPROM and Signature bytes reading.
Figure 63. Programming the Flash Waveforms
Figure 64. Programming the Flash Waveforms (continued)
Reading the Flash
The algorithm for reading the Flash memory is as follows (refer to Programming the Flash for details on Command and
Address loading):
1.
A: Load Command ‘0000 0010’.
2.
B: Load Address High Byte ($00 - $03/$07).
3.
C: Load Address Low Byte ($00 - $FF).
4.
Set OE to ‘0’, and BS 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 from DATA.
6.
Set OE to ‘1’.
$10
ADDR. HIGH
ADDR. LOW
DATA LOW
DATA
XA1
XA0
BS
XTAL1
WR
RDY/BSY
RESET
OE
12V
DATA HIGH
DATA
XA1
XA0
BS
XTAL1
WR
RDY/BSY
RESET
+12V
OE