w78e54 Winbond Electronics Corp America, w78e54 Datasheet - Page 4

• Manufacturer Part Number: w78e54
• Description: 8-bit Microcontroller
• Manufacturer: Winbond Electronics Corp America

EA/V
RST
ALE
PSEN
XTAL1
Normal
Normal
Normal
Normal
MODE
MODE
MODE
MODE
MODE
Flash
Flash
Flash
Flash
Flash
PP
No function in this mode.
This pin forces the processor to execute a program from the external ROM. When the
internal flash EEPROM is accessed as in the W78C54, this pin should be kept high.
V
This pin accepts the high voltage (12V) needed for programming the flash EEPROM.
RST, Reset, Input, active high.
This pin resets the processor. It must be kept high for at least two machine cycles in
order to be recognized by the processor.
Flash mode configuration pin, Input, active high.
RST is used to configure the flash operations. For details, see Flash Operations.
ALE, Address Latch Enable, Output, active high.
ALE is used to enable the address latch that separates the address from the data on
Port 0. ALE runs at 1/6th of the oscillator frequency. A single ALE pulse is skipped
during external data memory accesses. ALE goes to a high impedance state with a
weak pull-up during reset state.
Flash mode configuration pin, Input, active low.
ALE is used to configure the flash operations. For details, see Flash Operations.
PSEN , Program Store Enable, Output, active low.
This pin enables the external ROM onto the Port 0 address/data bus during fetch and
MOVC operations. PSEN goes to a high impedance state with a weak pull-up during
reset state
Flash mode configuration pin, Input, active high.
PSEN is used to configure the flash operations. For details, see Flash Operations.
EA , External Access, Input, active low.
PP
, Program Power supply pin, Input.
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DESCRIPTION
DESCRIPTION
DESCRIPTION
DESCRIPTION
DESCRIPTION
W78E54