Why do you need a 8051 to do this simple job?

Choose a simple lowpin count controller that fixes these problems.

export the data serial, SPI, or I2C.

Or take a simple ONE SHOT MMV set R en C to 1 sec.
Take a low cost PLD and add those pulses to a pin. Design a counter 5.
Add serial to parallel logic in the PLD for displaying the counted pulses and you can make a very low cost puls counter.

If you select a ISP PLD than you have a flexible solution for your problem.


Bert Regards.

PS. : When can I expect the reward ?