Rainbow Electronics AT90LS2343 - Manual (Page 38)

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AT90S/LS2323/2343
1004D–09/01
3. $002: $03 (indicates AT90S/LS2343 when signature byte $001 is $91)
Note: When both Lock bits are programmed (Lock mode 3), the signature bytes cannot be read
in the low-voltage Serial mode. Reading the signature bytes will return: $00, $01 and
$02.
Programming the Flash
and EEPROM Atmel’s AT90S2323/2343 offers 2K bytes of In-System Programmable Flash program
memory and 128 bytes of EEPROM data memory.
The AT90S2323/2343 is shipped with the On-chip Flash program and EEPROM data
memory arrays in the erased state (i.e., contents = $FF) and ready to be programmed.
The device supports a high-voltage (12V) Serial Programming mode and a low-voltage
Serial Programming mode. The +12V is used for programming enable only and no cur-
rent of significance is drawn by this pin. The low-voltage Serial Programming mode
provides a convenient way to download program and data into the device inside the
user’s system.
The program and EEPROM memory arrays in the AT90S2323/2343 are programmed
byte-by-byte in either programming modes. For the EEPROM, an auto-erase cycle is
provided within the self-timed write instruction in the low-voltage Serial Programming
mode.
During programming, the supply voltage must be in accordance with Table 15.
High-voltage Serial
Programming This section describes how to program and verify Flash program memory, EEPROM
data memory, Lock bits and Fuse bits in the AT90S2323/2343.
Figure 32. High-voltage Serial Programming
Table 15. Supply Voltage during Programming
Part Low-voltage Serial Programming High-voltage Serial Programming
AT90S2323 4.0 - 6.0V 4.5 - 5.5V
AT90LS2323 2.7 - 6.0V 4.5 - 5.5V
AT90S2323 4.0 - 6.0V 4.5 - 5.5V
AT90LS2323 2.7 - 6.0V 4.5 - 5.5V
RESET
XTAL1/PB3
GND
VCC
PB2
PB1
PB0
SERIAL DATA OUTPUT
SERIAL INSTR. INPUT
SERIAL DATA INPUT
SERIAL CLOCK INPUT
11.5 - 12.5V 4.5 - 5.5V AT90S/LS2323,
AT90S/LS2343