AT90S/LS4434 and AT90S/LS8535
86
The program and data memory arrays on the AT90S4434/8535 are programmed byte-by-byte in either programming
mode. For the EEPROM, an auto-erase cycle is provided within the self-timed write instruction in the Serial Programming
Mode.
During programming, the supply voltage must be in accordance with Table 37.
Parallel Programming
This section describes how to parallel program and verify Flash program memory, EEPROM data memory, Lock bits and
Fuse bits in the AT90S4434/8535.
Signal Names
In this section, some pins of the AT90S4434/AT908535 are referenced by signal names describing their function during
parallel programming. See Figure 67 and Table 38. Pins not described in Table 38 are referenced by pin name.
The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a positive pulse. The bit coding are shown
in Table 39.
When pulsing WR or OE, the command loaded determines the action executed. The command is a byte where the different
bits are assigned functions as shown in Table 40.
Figure 67.
Parallel Programming
Table 37.
Supply Voltage during Programming
Part
Serial Programming
Parallel Programming
AT90S4434
4.0 - 6.0V
4.5 - 5.5V
AT90LS4434
2.7 - 6.0V
4.5 - 5.5V
AT90S8535
4.0 - 6.0V
4.5 - 5.5V
AT90LS8535
2.7 - 6.0V
4.5 - 5.5V
AT90S4434/8535
VCC
+5V
RESET
GND
XTAL1
PD1
PD2
PD3
PD4
PD5
PD6
+12 V
RDY/BSY
OE
BS
XA0
XA1
WR
PB7 - PB0
DATA