Designing the Next- Designing the Next -Generation of Handheld Devices Generation of Handheld Devices Class 445 Class 445 Thursday, September 18th, 2003 Thursday, September 18th, 2003 Andrew Girson Andrew Girson 240- -558 558- -2014 2014 240 agirson@inhandelectronics.com @inhandelectronics.com agirson www.inhandelectronics.com www.inhandelectronics.com
Presentation Focus Presentation Focus A survey of the significant issues in the A survey of the significant issues in the development of system hardware and development of system hardware and system software for programmable system software for programmable handheld devices, based on 32- -bit bit handheld devices, based on 32 CPUs and operating systems CPUs and operating systems 2
Presentation Overview Presentation Overview � Market Opportunity & Design Challenges Market Opportunity & Design Challenges � � How Handheld Design is Different How Handheld Design is Different � � Designing a Handheld Designing a Handheld � 3
Handhelds - - A Growing Market A Growing Market Handhelds � Over 400M ARM CPUs shipped in 2001 Over 400M ARM CPUs shipped in 2001 � – majority of these CPUs in cellular telephones, majority of these CPUs in cellular telephones, – PDAs, and other wireless devices PDAs, and other wireless devices � Yet, cellular telephone penetration was Yet, cellular telephone penetration was � just 6% in China in 2000 just 6% in China in 2000 – US penetration 41% US penetration 41% – – Worldwide penetration 12% Worldwide penetration 12% – 4
Opportunity Opportunity � Mass Markets Mass Markets � – Merging multiple handhelds into one Merging multiple handhelds into one – – Bringing handhelds to everybody Bringing handhelds to everybody – � Vertical markets Vertical markets � – Bringing smart handhelds to new segments Bringing smart handhelds to new segments – – Upgrading “fixed Upgrading “fixed- -function” handhelds function” handhelds – � All Markets All Markets � – Leveraging new technologies Leveraging new technologies – 5
What This Means for Engineers What This Means for Engineers Opportunity Opportunity � � Volatility & Innovation Volatility & Innovation � � Design Challenges Design Challenges “make it smaller” “ruggedize ruggedize it” it” “make it run for weeks on a single charge” “make it smaller” “ “make it run for weeks on a single charge” “make it hands- -free” free” “add location- -based services” based services” “use this new wireless technology” “make it hands “add location “use this new wireless technology” 6
How Handheld Design is Different How Handheld Design is Different � Designers of handheld devices must Designers of handheld devices must � overcome all of the challenges of overcome all of the challenges of traditional embedded design, yet they traditional embedded design, yet they must also… must also… � …make it fit …make it fit � � …make it last …make it last � 7
How Handheld Design is Different How Handheld Design is Different It all comes down to... It all comes down to... “Form Factor” & “Battery Life” “Form Factor” & “Battery Life” 8
Designing a Handheld Designing a Handheld � Define user requirements Define user requirements � � Select a Form Factor Select a Form Factor � � Select a Display Select a Display � � Select Batteries Select Batteries � � Select a CPU & OS Select a CPU & OS � � Design system hardware platform Design system hardware platform � � Develop system software platform Develop system software platform � 9
Define User Requirements Define User Requirements � Will it be used outside? Will it be used outside? � � What types of data will be displayed? What types of data will be displayed? � � How will the user input data? How will the user input data? � � Is it likely to be dropped on a hard surface? Is it likely to be dropped on a hard surface? � � Could it get wet? Could it get wet? � � Will the user have ready access to AC power? Will the user have ready access to AC power? � � How will the user talk to the network? How will the user talk to the network? � 10
Select a Form Factor Select a Form Factor � PDA PDA � � Cell phone Cell phone � � Smartphone Smartphone � � Web Tablet Web Tablet � � Wearable Computer Wearable Computer � � Wireless Terminal Wireless Terminal � 11
Select a Form Factor Select a Form Factor � Develop mechanical specifications Develop mechanical specifications � – Package form factor and materials Package form factor and materials – – Display, battery, electronics, and input integration Display, battery, electronics, and input integration – – Manufacturability and assembly issues Manufacturability and assembly issues – – Environmental and ruggedization issues Environmental and ruggedization issues – 12
Select a Display Select a Display � Based on form factor Based on form factor � � Based on user interface requirements Based on user interface requirements � � Based on ambient environment Based on ambient environment � � indoor, outdoor, readable in sunlight, readable indoor, outdoor, readable in sunlight, readable � in low light, viewing angle, orientation in low light, viewing angle, orientation 13
Select a Display Select a Display � Different Technologies Different Technologies � � STN, TFT, OLED STN, TFT, OLED � � reflective, transmissive, transflective reflective, transmissive, transflective � � Backlights Backlights - - CCFT, EL, LED (watch out for CCFT, EL, LED (watch out for � power consumption and noise) power consumption and noise) � Always get: Always get: � � a demo of the working display in the a demo of the working display in the � environment in which it will be used environment in which it will be used � a power measurement with and without a power measurement with and without � backlighting backlighting 14
Select Batteries Select Batteries � Two Types of Batteries Two Types of Batteries � – Primary Primary – – Rechargeable Rechargeable – � Each has advantages and disadvantages Each has advantages and disadvantages � � Make sure you estimate battery life for Make sure you estimate battery life for � “likely” user scenarios “likely” user scenarios 15
Characteristics of Primary Batteries Characteristics of Primary Batteries � Primary batteries have higher energy Primary batteries have higher energy � density than rechargeables rechargeables density than � Carbon Carbon- -Zinc and Alkaline are commodity Zinc and Alkaline are commodity � “drugstore” batteries “drugstore” batteries � Lithium batteries are best all Lithium batteries are best all- -around around � performers with very flat discharge curves, performers with very flat discharge curves, high energy density, and excellent shelf high energy density, and excellent shelf life and low- -temperature capacity temperature capacity life and low 16
Comparison of Primary Battery Comparison of Primary Battery Types Types Chemistry Cell Cell Gravimetric Volumetric Capacity Voltage Capacity Energy Energy loss per (V) (mAh) Density Density YEAR (WHr/kg) (WHr/l) (@ 20C) Carbon- 1.5 10-5000 105-195 100-180 5% Zinc Alkaline 1.5 10-5000 125-225 150-440 4% S ilver 1.5 5-200 155-285 250-500 3% Oxide Zinc Air 1.4 30-1000 245-455 470-1450 5% (sealed) Lithium 1.5, 3.0 10-3000 32-260 340-500 1% 17
Characteristics of Rechargeable Characteristics of Rechargeable Batteries Batteries � Rechargeable batteries are reusable, reducing Rechargeable batteries are reusable, reducing � cost and environmental issues cost and environmental issues � Li Li- -Ion batteries are best performers, but are Ion batteries are best performers, but are � costly and require tight control of charging costly and require tight control of charging algorithms algorithms � NiMH and Li NiMH and Li- -Ion can be dangerous if Ion can be dangerous if � overcharged overcharged � NiCad is simpler with better overcharging NiCad is simpler with better overcharging � tolerance, but lower performing tolerance, but lower performing 18
Comparison of Rechargeable Comparison of Rechargeable Battery Types Battery Types Chemistry Cell Cell Gravimetric Volumetric Capacity Voltage Capacity Energy Energy loss per (V) (mAh) Density Density MONTH (WHr/kg) (WHr/l) (@ 20C) NiCad 1.2 50-5000 55 170 10% NiMH 1.2 10-5000 70 250 15% Li-Ion 3.6 25-1600 120 350 3% 19
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