04/07/2023 1

DIGITAL PRIVATE BRANCH EXCHANGE CPU DESIGN USING ARM 9 PROCESSOR

By

M.Muneeswaran (9910108007)

II M.Tech /EST

Kalasalingam University, KrishnanKovil.

Guided by

Mr. D.Ganesha Perumal ,

AP-I/EEE

Kalasalingam University, KrishnanKovil.

04/07/2023 2

PRIVATE BRANCH EXCHANGE

Introduction:

• Private Branch Exchange means a private telephone system which is part of a larger network system [Public Switched Telephone Network (PSTN)] that exchange information.

• PBX is installed in a business location to facilitate communication between people inside the organization while allowing access to adequate external telephone lines.

• Analog PBX shows result in low voice and cross talk errors.

04/07/2023 3

ABSTRACT

• Design and Implement a Digital PBX CPU system Using 32-Bit ARM processor which supports more than 100-Extension lines and 20-Trunk lines. The ARM 9 (S3C2440A) based DPBX CPU performs:– Establish a connection between two terminals during a

phone call.– Maintain a connection as long as the users require it.– Provide call details for accounting purposes.

04/07/2023 4

DPBX CPU USING PENTIUM I PROCESSOR

• Availability of Pentium I is difficult(obsolete model).• It support 100-Extension and 12-Trunk lines(support upto 200 MHz)• Larger in CPU size.• High CPU cost.

04/07/2023 5

DPBX CPU USING ARM-9 PROCESSOR

• Processor Availability.• It support more than 100-Extension and 20-trunk lines(support upto

533Mhz).• Compact CPU size.• Reduced CPU cost.• Low power Consumption.

04/07/2023 6

BLOCK DIAGRAM

Extension Circuit

Extension Circuit

PCM Codec

PCM Codec

Digital cross point CPU

ARM 9 Processor

DTMF Transceiver

Tone section

PCM Codec

Trunk Circuit

Trunk line

Phone 2

Phone 1FLASH MEMORY

SDRAM

EEPROM

04/07/2023 7

DIGITAL CROSS POINT CPU CARD

04/07/2023 8

INTERFACING CIRCUIT FOR DIGITAL CROSS POINT SECTION

04/07/2023 9

MT8980( DIGITAL CROSS POINT )SECTION

• TDM(Time Division Multiplexing) is used for transmitting several message signals over a single communication channel by dividing the time frame into slots, one slot for each message signal

• It has 8- TDM 2048kbit/s ST-BUS stream input and stream output line.• Each stream has 32-channel.• 4(A0-A4)- address line for selecting channel.• A5 is used to selecting control registers.• In control registers, we can select connection memory high , connection

memory low & data mode.• Every read (or) write operation, data acknowledgement signal received in

DTA.• Necessary clock signal 4.096MHz(C4i) & 8kHz(F0i-Framing 0-type --

frame synchronization pulse for the 2048 kbit/s ST-BUS) is generated by using Frequency divider and 4-bit Synchronous counter.

04/07/2023 10

CPU control circuit design

04/07/2023 11

NON-BLOCKING SWITCHING

MT8980#1

MT8980#2

MT8980#3

MT8980#4

STi0-STi7

STi8-STi15

STo0-STo7

STo8-STo15

04/07/2023 12

READING SPECIFIC CHANNEL INFORMATION

Parallel to serial converter

ChannelSelection

Serial Output to STREAM INPUT

Parallel Input Data from Control circuit

04/07/2023 13

WRITING SPECIFIC CHANNEL INFORMATION

Serial to Parallel converter

ChannelSelection

Parallel Output Data to Control Circuit

Serial Input from STREAM OUTPUT

04/07/2023 14

8KHZ & 4.096MHZ FREQUENCY

04/07/2023 15

OUTPUT STREAM AT POWER UP CONDITION

04/07/2023 16

OUTPUT STREAM AT INITIALIZATION WITH ALL CHANNEL AS 0XFF

04/07/2023 17

OUTPUT STREAM WHEN SWITCHING WITH 1MS INPUT STREAM

04/07/2023 18

CONCLUSION

• Pentium-I based digital PBX CPU is replaced with 32-bit ARM 9 (S3C2440A) Processor. When this S3C2440A based CPU, it supports more than 100 extension ports and 20 trunk lines.

• In Digital cross point CPU card, Reading information & Writing information & Switching ST-BUS Stream input and output is successfully with ARM 9 (S3C2440A) Processor.

04/07/2023 19

REFERENCES

• Simon Segars, “The ARM9 Family - High Performance Microprocessors for Embedded Applications”, Proceedings ICCD '98. International Conference on, pp. 230 - 235 ,oct 1998.

• Christiensen C. Arandilla, Joseph Bernard A. Constantino, Alvin Oliver M. Glova Anastacia P. Ballesil-Alvarez, Joy Alinda P. Reyes, “High-Level Implementation of the 5-Stage Pipelined ARM9TDM Core”, TENCON 2010 - 2010 IEEE Region 10 Conference, pp. 1696 – 1700, Nov 2010.

• Azlan Bin Sulaiman, Mohd Sharifuddin Bin Mohd Nordin, Namazi Bin Azhari , Dr. Jalil Md. Desa, “Samsung ARM9 S3C2440A Hardware Core Circuit Design”, 2011 IEEE Symposium on Computers & Informatics, pp.352-356, 2011.

• Lei Zhang and Zhengfeng Wang, “Design of Embedded Control System Based on ARM9 Microcontroller”,Internation conference on electrical and control enginnering,pp. 3579-3582, oct 2010.

• Mischar schwartz,“History of Communication”,IEEE communication Magazine, pp.13-15, December 2008.

04/07/2023 20

THANK YOU