at90s2323 ATMEL Corporation, at90s2323 Datasheet - Page 44

• Manufacturer Part Number: at90s2323
• Description: 8-bit Microcontroller With 2k Bytes Of In-system Programmable Flash At90s2323 At90ls2323 At90s2343 At90ls2343
• Manufacturer: ATMEL Corporation

Data Polling EEPROM
Data Polling Flash
44
AT90S/LS2323/2343
7. At the end of the programming session, RESET can be set high to commence
8. Power-off sequence (if needed):
When a byte is being programmed into the EEPROM, reading the address location
being programmed will give the value P1 until the auto-erase is finished, and then the
value P2 will be given. See Table 18 for P1 and P2 values.
At the time the device is ready for a new EEPROM 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 values P1 and P2, so when programming these values, the user will have to wait
for at least the prescribed time t
for t
of addresses that are meant to contain $FF can be skipped. This does not apply if the
EEPROM is reprogrammed without first chip-erasing the device.
Table 18. Read Back Value during EEPROM Polling
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
erased device contains $FF in all locations, programming of addresses that are meant
to contain $FF can be skipped.
Figure 36. Low-voltage Serial Downloading Waveforms
Part
AT90S2323
AT90S2343
SERIAL DATA OUTPUT
SERIAL CLOCK INPUT
Set CLOCK/XTAL1 to “0”.
Set RESET to “1”.
Turn V
WD_PROG
normal operation.
SERIAL DATA INPUT
CC
value. As a chip-erased device contains $FF in all locations, programming
PB0(MOSI)
PB1(MISO)
PB2(SCK)
power off.
MSB
MSB
WD_PROG
WD_PROG
before programming the next byte. See Table 22
before programming the next byte. As a chip-
P1
$00
$00
P2
$FF
$FF
LSB
LSB
1004D–09/01