How to select the right MCU for your
design
Maryala Srinivas
Founder & Managing Director
Wine Yard Technologies, Hyderabad
Natural Tendency
A Design Engineer looks for
 Greater Performance
 More Memory
Results in
needless extra cost & Complexity
Criteria for selecting MCU
1. 8 bit / 16 bit / 32 bit
2. In-built features like ADC/EEPROM
3. Packaging (Dual in Line / Quad flat
4.
5.
6.
7.
pack)
Power Consumption
Amount of on chip RAM & ROM
Number of I/O pins
Cost efficiency
Temperature
Sensor
ADC
Microcontroller
Driver
Relay
AC Temperature Controller
Microcontroller
Temperature
Sensor
Inbuilt
ADC
Driver
Relay
AC Temperature Controller modified
Design
Time Input
EEPROM
Street Light Controller
Microcontroller
Driver
Relay
Microcontroller
Time Input
Inbuilt
EEPROM
Driver
Relay
Street Light Controller
Modified Design
Packaging: Dual in Line / Quad Flat pack
Power Consumption
RAM – ROM & I/O Pins
MCU Erase / rewrite rates
Customers comment sometimes there are disadvantages
to having more memory on an MCU
During production, erase/rewrite speed is most
important thing for speed production
Newer classes of MCUs with up to 512k bytes of flash
memory can be erased and rewritten in as little as two
to three seconds,
Compared to other MCUs that can require as much as 40
seconds.
RISC or CISC
As performance demands increase, engineers tend to
switch from CISC to RISC
New MCUs based on the CISC architecture run at 80
MHz.
Applications such as listening to music or e-learning
where music or speech must be clear and high quality,
these new CISC product families provide an attractive
option.
RISC or CISC
Toshiba TMP92CZ26A
Fastest 32-bit Color Display CISC Microcontroller is a
new 32-bit CISC MCU that runs at 80 MHz
RISC and CISC architectures are becoming more and
more alike.
PowerPC 601 (RISC) supports more instructions than
Pentium (CISC)
Further more, today's CISC chips use many techniques
formerly associated with RISC chips
Cost Efficiency
DTSi Technology
Usually the single sparkplug doesn’t actually gets the
optimum air-fuel mixture to cause complete
combustion.
The DTSi technology actually incorporates two
sparkplugs at either ends of the combustion chamber
of the engine.
DTSi Technology
So with the twin spark the majority area of the air-fuel
mixture is considered for the complete combustion
which results in
 Faster and better combustion
 Reduction of exhaust gases
 Generating high power
DTSi Technology
Accurate ignition timings at different speeds is major
task controlled by the controller by
CDI(Computerised Direct Ignition) system
New generation throttle response system
The digital CDI in the new Pulsar, which features an
advanced MCU handles the spark delivery.
DTSi Technology
• The programed chip’s memory contains the optimum
ignition timing for any given engine rpm, thereby
squeezing out the best performance characteristics
from the combustion chamber
• Motorola MPC 555
• POWER PC Performance Optimization With
Enhanced RISC - Performance Computing
Criteria for selecting MCU
Availability of
 Assembler
 Code-efficient compiler
 Technical Support
Criteria for selecting MCU
Ready Availability in needed
quantities
Wine Yard’s Bitter Experience - 2006
Street Light Automation Project in Nalgonda &
Warangal Municipality with AT89S8252 MCU
8K flash – 1000 write / erase cycles
2K EEPROM – 1,00,000 write / erase cycles
3 – 16 bit counters
9 – interrupt sources
Interrupt recovery from power down
Wine Yard’s Bitter Experience - 2006
ATMEGA 2560
4KB EEPROM
256KB Flash
2- 8 bit counters
4 – 16 bit counters
Internal calibrated oscillator
Design Applications
with RTOS
Checklist to choose your MCU
Support for OS
Footprint required by OS
Maximum number of tasks
Checklist to choose your MCU
QNX Neutrino
ARM, POWER PC, X86, Pentium
Needs 64K Kernel ROM
Checklist to choose your MCU
VxWorks:
ARM, Power PC, Motorola Coldfire
RTLinux:
X86, Pentium, Power PC, ARM
Needs 4MB footprint
Suitable MCU makes your product
UNIQUE
Thank you……!!