TS87C54X2-EIE 查看數據表（PDF） - Atmel Corporation

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TS87C54X2-EIE

8-bit CMOS Microcontroller 16/32 Kbytes ROM/OTP

Atmel Corporation 

TS80C54X2/C58X2

TS87C54X2/C58X2

MNEMONIC

ALE/PROG

PSEN

EA/VPP

XTAL1

XTAL2

Table 3. Pin Description for 40/44 pin packages

PIN NUMBER TYPE

NAME AND FUNCTION

30 33

27

O (I) Address Latch Enable/Program Pulse: Output pulse for latching the low byte

of the address during an access to external memory. In normal operation, ALE

is emitted at a constant rate of 1/6 (1/3 in X2 mode) the oscillator frequency,

and can be used for external timing or clocking. Note that one ALE pulse is

skipped during each access to external data memory. This pin is also the program

pulse input (PROG) during EPROM programming. ALE can be disabled by

setting SFR’s AUXR.0 bit. With this bit set, ALE will be inactive during internal

fetches.

29 32

26

O Program Store ENable: The read strobe to external program memory. When

executing code from the external program memory, PSEN is activated twice each

machine cycle, except that two PSEN activations are skipped during each access

to external data memory. PSEN is not activated during fetches from internal

program memory.

31 35

29

I External Access Enable/Programming Supply Voltage: EA must be externally

held low to enable the device to fetch code from external program memory

locations 0000H and 3FFFH (54X2) or 7FFFH (58X2). If EA is held high, the

device executes from internal program memory unless the program counter

contains an address greater than 3FFFH (54X2) or 7FFFH (58X2). This pin also

receives the 12.75V programming supply voltage (VPP) during EPROM

programming. If security level 1 is programmed, EA will be internally latched

on Reset.

19 21

15

I Crystal 1: Input to the inverting oscillator amplifier and input to the internal

clock generator circuits.

18 20

14

O Crystal 2: Output from the inverting oscillator amplifier

6

Rev. C - 15 January, 2001

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