El pulsador que estas usando es normalmente abierto o cerrado??
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4.10 EA/VPP
External Access Enable. EA must be strapped to GND in order to enable the device to fetch
code from external program memory locations starting at 0000H up to FFFFH. Note, however,
that if lock bit 1 is programmed, EA will be internally latched on reset.
EA should be strapped to VCC for internal program executions.
This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming.
Si, esta correctamente conectado,Estás seguro que tienes el integrado conectado correctamente?
Dice que los pines no corresponden...


89C51 es lo mismo que no decir nada, faltan los apellidos del chip.
Es muy probable que no lo puedas leer porque no se pueda leer. Lo normal es que esté protegido.