Assembly for VENDING Machine ARM processor please help! :)

I am new and I dont now much about arm assembly.I have a task on arm assembly and if anyone knows i would be grateful if could help me!!

Task :

To write a program in assembly to corresponding ARM processor, which could be used as a vending machine with snack and beverages.
The slot machine accepts coins of 1, 2, 5, 10, 20 minutes and 1 and 2 €. Each product will have its own value. Then depending on the money that will introduce the user and the product selection you make, the machine will compare if the money is sufficient for purchasing the selected product. If fewer machine money will not give the product, while if more will return the change.


The algorithm is as follows:
• The user inserts money.
• The amount required to pay the user could follow the following charges:
1. A chocolate costs 1 €.
2. An orange juice equals 70 minutes.
3. A box of cookies 85 minutes.
4. A croissant 1.20 €.
• The user selects the product he wants.
• The system makes the comparison between the money introduced by the user and the commercial value of the product selected.
• Depending on the result of the comparison are the following possibilities:
1. Money is less so the machine does not produce the product.
2. If sufficient money the machine will provide the product and calculate the change.
3. If money is exactly equal to the value of the product the machine produces the product.

• The following inputs control the system functions:
10H: chocolate selection switch.
11H: orange juice selection switch.
12H: Cookie Selector Switch.
13H: Select Switch croissants.
• The following outputs control system functions:
10H: return activation switch for the change.
11H: activation switch for the production of selected product


Thank you for your time!