ECE 477RELIABILITY & SAFETY ANALYSIS

Team 5 – myATM

Xue Yuan Wong

OVERVIEW

Automated Teller Machine (ATM)

Use face recognition technology to verify identity

4-digit PIN

Read/Write cash card via RFID

Touchpad to navigate user menu

Occupancy sensor to detect user

CRITICALITY LEVELS

High criticalityFailure that could potentially injure or harm the

user.Acceptable failure rate, λ <

Medium criticalityFailure that causes component(s) to damage and

therefore not being able to function normally anymore.

Acceptable failure rate, λ <

CRITICALITY LEVELS

Low criticalityFailure that results non-ideal operation of the

component and does not harm the userAcceptable failure rate, λ <

COMPONENT ANALYSIS

Microcontroller (Microchip PIC18F24J11)Complex architecturePerform various tasks (eg: sample keypad

buttons, occupancy sensor, RFID data, control modulation)

Switching regulators (TI LM2675-3.3/5.0)Handles large amount of current

COMPONENT ANALYSIS

RFID read/write base station (Atmel U2270B)Has 16 pins. Multiple modules inside the chip.

On-chip power supply circuitAntenna driver circuitFrequency generatorSignal processing circuit

(modulation/demodulation)Fast switching signals. Generate heat easily.

Paramaeter Description Value Comments

C1 Die complexity 0.28 16-bit MOS microprocessor

πT Temperature coefficient 0.98 Assume TJ < 85 °C

C2 Package failure rate 0.013 28 pins non-hermetic SMT component

πE Environment factor 2.0 GF (ground fixed)

πQ Quality factor 10 Commercial level

πL Learning factor 1.0 Started production in March 2011. Production > 2 years

λP Failure rate / 106 hours 3.004

1/ λP MTTF 332889 hours = 38 years

PIC18F24J11 Microcontroller

Paramaeter Description Value Comments

C1 Die complexity 0.01 MOS linear gate with approximately 1 to 100 transistors

πT Temperature coefficient 16 Assume TJ < 100 °C

C2 Package failure rate 0.0034 8 pins non-hermetic SMT component

πE Environment factor 2.0 GF (ground fixed)

πQ Quality factor 10 Commercial level

πL Learning factor 1.0 Started production in 2004 Production > 2 years

λP Failure rate / 106 hours 1.668

1/ λP MTTF 599520 hours = 68 years

LM2675 Switching Regulator

Paramaeter Description Value Comments

C1 Die complexity 0.01 MOS linear gate with approximately 1-100 transistors

πT Temperature coefficient 16 Assume TJ < 100 °C

C2 Package failure rate 0.0072 16 pins non-hermetic SMT component

πE Environment factor 2.0 GF (ground fixed)

πQ Quality factor 10 Commercial level

πL Learning factor 1.0 Started production in 2005 Production > 2 years

λP Failure rate / 106 hours 1.744

1/ λP MTTF 573394 hours = 65 years

U2270B RFID Read/Write Base Station

Section A - Power Supply Block

Section B - Microcontroller Block (1)

Section B - Microcontroller Block (2)

Section C – RFID Block

FMECA CHART

Failure No.

Failure Mode

Causes Effects Method of Detection

Criticality Remarks

A1 VDD1 = 0VorVDD2 = 0V

-Failure of switching regulator-L1,L2 open-circuit or short-circuit

-No keypad input-Fail to access RFID cash card-Cannot detect user

Intel board watchdog

Low

A2 VDD1 > 5VorVDD2 > 3.3V

- Failure of switching regulator

-Partial loss of ATM functionality

Intel board watchdog

Medium

Section A – Power Supply Block

FMECA CHART

Failure No.

Failure Mode

Causes Effects Method of Detection

Criticality

Remarks

B1 No keypad input is detected(RB1 = 0V,RB2 = 0V,RB3 = 0V)

-Keypad buttons become less sensitive

-Could not input PIN to authenticate user

By observation

Low

B2 Microcontroller UART becomes not responsive

-Failure of MAX3232-C4,C5,C6,C7 open-circuit or short-circuit

-Loss communication between microcontroller and Intel Atom Board

-Intel board watchdog-Observation

Medium

Section B – Microcontroller Block

FMECA CHART

Failure No.

Failure Mode

Causes Effects Method of Detection

Criticality

Remarks

B3 Pin “PIR” = 0V

Potential failure of occupancy sensor

-Fail to detect user- ATM stays at inactive mode

By observation

Low

Section B – Microcontroller Block

FMECA CHART

Failure No.

Failure Mode

Causes Effects Method of Detection

Criticality

Remarks

C1 Pin CFE continuously receives 0 or 1

-Potential failure of voltage translator (MAX3373)

- Could not control modulation-Unable to read/update cash card

By observation

Low

C2 Modulation frequency out of tolerance(f > 125 kHzorF < 125 kHz)

-R3 short-circuit or open circuit- Internal modulation circuitry issue

-Cannot detect cash card-Fail to read/update cash card

By observation

Low

Section C – RFID Block

FMECA CHART

Failure No.

Failure Mode

Causes Effects Method of Detection

Criticality

Remarks

C3 Data rate out of tolerance(125 kHz / 32)

- Incorrect register configuration of RFID cash card- Potential failure of cash card

-Unable to read RFID cash card

By observation

Low

Section C – RFID Block

QUESTION