Rainbow Electronics AT90LS4433 - Manual (Page 95)

95
AT90S/LS4433
1042G–AVR–09/02
Data Polling Flash When a byte is being programmed into the Flash, reading the address location being
programmed will give the value $FF. At the time the device is ready for a new byte, the
programmed value will read correctly. This is used to determine when the next byte can
be written. This will not work for the value $FF, so when programming this value, the
user will have to wait for at least t
WD_PROG
before programming the next byte. As a chip-
erased device contains $FF in all locations, programming of addresses that are meant
to contain $FF can be skipped.
Figure 67. Serial Programming Waveforms
MSB
MSB
LSB
LSB
SERIAL CLOCK INPUT
PB5(SCK)
SERIAL DATA INPUT
PB3(MOSI)
SERIAL DATA OUTPUT
PB4(MISO)