Rainbow Electronics AT90LS4433 - Manual (Page 89)

89
AT90S/LS4433
1042G–AVR–09/02
G: Write Data High Byte
1. Set BS to “1”. This selects high data.
2. Give WR a negative pulse. This starts programming of the data byte. RDY/BSY
goes low.
3. Wait until RDY/BSY goes high to program the next byte.
(See Figure 64 for signal waveforms.)
The loaded command and address are retained in the device during programming. For
efficient programming, the following should be considered:
• The command needs to be loaded only once when writing or reading multiple
memory locations.
• Address High Byte needs to be loaded only 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 apply to EEPROM programming and Flash, EEPROM and
signature bytes reading.
Figure 63. Programming the Flash Waveforms
$10 ADDR. HIGH ADDR. LOW DATA LOW DATA
XA1
XA0
BS
XTAL1
WR
RDY/BSY
RESET
OE
12V