problems with running at89s52 board

AT89C51 Datasheet said:

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 when 12-volt programming is selected.

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Manual of a commercial tester said:

EA/VPP (AT89C51/52) or RST/VPP (AT89C1051/2051)
This pin will be taken high during flash memory write and erase operations. EA/VPP (AT89C51/52) or RST/VPP (AT89C1051/2051) will generally be fixed either high or low when the board is carrying out its normal mission, depending on whether the application uses external addressing or runs entirely on its internal memory. There are four things to remember about this pin.

1. In certain parts of the Atmel documentation, Atmel recommends that this pin be “strapped” to VCC or ground. Please interpret the word “Strapped” to mean “connected by a 500 W resistor.” The resistor will supply the desired 0 or 1 logic level during normal board operation, but the tester can also change the level easily as needed when testing the microcontroller or when writing its flash memory.

2. The pin must be accessible to the tester, i.e. it must be contactable by a probe in a vacuum fixture (bedof-nails fixture).

3. Atmel makes two versions of the microcontroller. One writes flash memory with 5 volts on this pin; the other writes flash memory with 12 volts on this pin. If you are using the 12-volt part, and if you need to connect other components to the EA/VPP pin for any reason, you will need to provide some way of protecting the other components from being damaged by the 12-volt level. The AT89C1051/2051 are only available with 12-volt programming.

4. For the AT89C1051/2051, if an RC circuit is used to generate power-up reset, don’t tie the capacitor directly to the RST pin. Put a resistor in between so that the tester will not have to take time charging the capacitor to 12 volts with each programmed byte.

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