$1.$ An AT$89$C$52$ microcontroller oscillator works with $12$ MHz crystal. There is an LED connected to the $8$th pin of the P$1$ port. Write the codes that turn this LED on and off for the periods given below.

a$.$ 'delay$1\text{'}$

b$.$ 'delay$2\text{'}$

c$.$ 'delay$3\text{'}$

$2.$ An AT$89$C$52$ microcontroller oscillator works with $12$ MHz crystal. Write the codes that generate square waves with frequencies as requested below on the $8$ th pin of the P$1$ port.

a$.\text{'}$f$1\text{'}$

b$.\text{'}$f$2\text{'}$

c$.\text{'}$f$3\text{'}$

$3.$ An AT$89$C$52$ microcontroller oscillator works with $4$ MHz crystal. There is an LED connected to the $8$th pin of the P$1$ port. Write the codes that turn this LED on and off for the periods given below.

a$.$ 'delay$1\text{'}$

b$.$ 'delay$2\text{'}$

c$.$ 'delay$3\text{'}$

$4.$ Repeat the question $3$ for $11\mathrm{.}0592$ MHz $.$

$5.$ Repeat the question $3$ for $16$ MHz $.$