Page 179 - DCAP210_INTRODUCTION__TO_MICROPROCESSORS

Unit 12: The Stacks

505 plc, and Panel View Plus1000 HMI. Notes

Result -- According to the company, this system allowed for three fewer employees per shift.
By decreasing the number of employees, the company reduced manpower turnover and
injuries. Straighter and neater stacks could not be achieved using the original manual system.
With the automated system the robots can stack precisely and also rotate tapered boards
every other part which allows for more even and straighter stacks.
Questions:
1. Explain the basic challenges which occur in automated stacking system.
2. How automated stacking systems overcome the manpower problems?

12.5 Summary

• A stack is a restricted data structure, because only a small number of operations are performed
on it.

• Elements are removed from the stack in the reverse order to the order of their addition:
therefore, the lower elements are those that have been on the stack the longest.

• If the stack is full and does not contain enough space to accept the given item, the stack is then
considered to be in an overflow state.
• If the stack is empty then it goes into underflow state.

12.6 Keywords

LIFO: Last In First Out, this is the way to implement the stack. If a data insert first in stack it will
remove at the last position.
POP: Pop is an operation to perform the deletion on the stack.

PSW: It stands for Program Status Word. It is an additional register pair in 8085, is made up of
the Accumulator and the Flag registers.
PUSH: Push is an operation to insert the data into the stack.

SP: The 8085 uses a 16 bit register to know where the stack top is located, and that register is
called the SP (Stack Pointer).

1. Write the steps to insert the data into the stack.
2. Write an assembly program to add two numbers.

12.7 Self-Assessment Questions

1. The stack is an area of memory identified by the programmer for temporary storage of
information.
(a) True (b) False
2. The stack is a ……. Structure.

(a) Last In First Out (b) First In Last Out
(c) both (d) none

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