TS80C54X2XXX-MCE ATMEL Corporation, TS80C54X2XXX-MCE Datasheet - Page 7

• Manufacturer Part Number: TS80C54X2XXX-MCE
• Description: At87c54x2, Ts87c54x2
• Manufacturer: ATMEL Corporation

Table 5-1.
4431E–8051–04/06
MNEMONIC
MNEMONIC
ALE/PROG
EA/V
XTAL1
XTAL2
PSEN
PP
Pin Description for 40/44 pin packages
DIL
30
29
31
19
18
PIN NUMBER
PIN NUMBER
LCC
33
32
35
21
20
VQFP 1.4
27
26
29
15
14
TYPE
TYPE
O (I)
O
O
I
I
NAME AND FUNCTION
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.
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.
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 (V
EA will be internally latched on Reset.
Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock
generator circuits.
Crystal 2: Output from the inverting oscillator amplifier
PP
) during EPROM programming. If security level 1 is programmed,
Name And Function
AT/TS8xC54/8X2
7