MuP-Design-Project

Soda Dispensing Machine Design done as a part of Second Year Computer Science Course : Microprocessors and Interfacing (CS-F241) Author : Bhavya Saraf, B.E. Computer Science, BITS Pilani K.K. Birla Goa Campus

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Problem Statement

Make a Soda Dispencing Machine that can dispence three different types of drinks in three different quantities : Small, Medium and Large. There are buttons to select cold drink and sizes. LED's are available with each button. Whenever choice is made and user enters the required number of coins, corresponding LED's glow and dispencing is done. The machine cancels dispencing in cases when the drink is not available in sufficient quantity or the incorrect number of coins are entered. There are LED's to indicate those too.

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Flow Chart

• START: This is the idle phase. No LEDs glow during this time.
• DRINK_TYPE_SELECTED: User presses the button corresponding to the drink he/she wants. The LED corresponding to that drink glows.
• DRINK_QTY_SELECTED: User presses the button corresponding to the amount of drink he/she wants. The LED corresponding to that drink glows.
• SUFFICIENCY CHECK: It checks whether the required amount of the drink ordered by the customer is available or not.
• GLOW NOT AVAILABLE: If the drink is not available, this glows the NOT AVAILABLE LED corresponding to the drink ordered.
• DISPENSE_SELECTED: User presses the dispense button after entering the required number of coins.
• VALIDITY CHECK: It checks whether the user entered the required number of coins or not.
• DISPENSE: If the user entered the right number of coins, then the drink is dispensed and the DISPENSE LED glows throughout the dispense process.

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Hardware Used

Sr No.	Device	Description	Quantity	Brief Purpose
1	OR Gates	2 Input OR Gates	10	For Memory Interfacing
2	NOT Gates	Not Gate	2	To Generate MEMR', MEMW' IOR', IOW' signals
3	74LS138	Decoder	2	Decding IO and Memory Devices
4	74LS245	Buffer	2	Help in Bidirectional Data Transfer
5	74LS373	Latch	3	Demultiplexing Address and Data Lines
6	2732	4 KB ROM	4	For Code Segment(Write Only)
7	6116	2 KB RAM	2	For Data Segment(Read, Write)
8	8086	Microprocessor	1	Execute Instructions, Generate IO Signals
9	8253	Programmable timer	2	For Interrupts and Dispesing Duration
10	8255	Programmable Peripheral Device	2	For Interfacing Buttons and LED's
11	8259	Programmable Interrupt Controller	1	Generating Maskable Interrupts
12	ADC0808	Analog To Digital Converter	1	To Convert Coin Detector Analog signal to Digital Signal
13	Button	Button	7	For User To choose drinks, sizes and dispence
14	L293D	Push-Pull 4 channel	3	Control Stepper Motor
15	LED	Red LEDs	10	To indicate current choice
16	Stepper Motor	Unipolar Stepper Motor	3	To Dispence Drink
17	MPX4250	Pressure Sensor	1	Detect Number of Coins
18	SW-SPDT-MOM	Momentary Interactive Switch	1	Processor Reset

Interfacing

Memory
RAM : 2KB+2KB = 4 KB
ROM : 8KB+8KB = 16KB

• Random Access Memory (RAM):
  Starting address – 02000H
  Ending address – 02FFFH
  Even bank begins at 02000H and ends at 02FFEH
  Odd bank begins at 02001H and ends at 02FFFH
  
• Read Only Memory (ROM):
  

1. ROM 1(8 KB)
   Starting address – 00000H
   Ending address – 01FFFH
   Even bank begins at 00000H and ends at 01FFEH
   Odd bank begins at 00001H and ends at 01FFFH
   
2. ROM 2(8 KB)
   Starting address – FE000H
   Ending address – FFFFFH
   Even bank begins at FE000H and ends at FFFFEH
   Odd bank begins at FE001H and ends at FFFFFH
   

IO (Using I/O Mapped I/O)
Mapping of 8255(1):
Port A: 00h
Port B: 02h
Port C: 04h
Control Register: 06h
Mapping of 8255(2):
Port A: 10h
Port B: 12h
Port C: 14h
Control Register: 16h
Mapping of 8253(1):
Counter 0: 20h
Counter 1: 22h
Counter 2: 24h
Control Register: 26h
Mapping of 8253(2):
Counter 0: 40h
Counter 1: 42h
Counter 2: 44h
Control Register: 46h
Mapping of 8259:
Address 0: 30h
Address 1: 32h