SAKC505L Просмотр технического описания (PDF) - Infineon Technologies

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SAKC505L

8-Bit CMOS Microcontroller

Infineon Technologies 

C505L

Table 1

Pin Definitions and Functions (cont’d)

Symbol

Pin Number I/O*) Function

RESET

43

PSEN

44

I

RESET

A high level on this pin for two machine cycles while the

oscillator is running resets the device. An internal diffused

resistor to VSS permits power-on reset using only an

external capacitor to VDD.

O The Program Store Enable

output is a control signal that enables the external program

memory to the bus during external fetch operations. It is

activated every three oscillator periods except during

external data memory accesses. Remains high during

internal program execution. This pin should not be driven

during reset operation.

ALE

45

O The Address Latch Enable

output is used for latching the low-byte of the address into

external memory during normal operation. It is activated

every three oscillator periods except during an external data

memory access. When instructions are executed from

internal program memory (EA = 1), the ALE generation can

be disabled by bit EALE in SFR SYSCON. This pin should

not be driven during reset operation.

EA

46

I

External Access Enable

This pin must be held at high level. Instructions are fetched

from the internal OTP memory when the PC is less than

8000H. Instructions are fetched from external program

memory, when the PC is greater than 7FFFH. This pin must

not be held at low level.

*) I = Input

O = Output

Data Sheet

8

06.99

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