CompE 460 Real-Time and Embedded Systems Lecture 2 – Interview and Design Process

Click to edit Master title style Agenda Prayer/Thoughts Job Interview for Erilyn Engineering Lab #2 Microprocessor Selection

Click to edit Master title style Erilyn Engineering Job Interview

Click to edit Master title style Erilyn Engineering Job Expectations First Assignment Processor Selection

Click to edit Master title style Microprocessor Selection What are some of the things you need to consider when selecting a processor or controller? Performance Price Power Efficiency Run mode Sleep mode Quality of Development Tools Compatibility with earlier processors Vendor Roadmap Life Expectancy Military Versions Availability as stand-alone chip or licensable core Flexibility FPGA fabric, reconfigurable?

Click to edit Master title style Processor Performance Benchmarks Lots of Benchmarks out there (some good, some very misleading) MIPS – Millions of instructions per second –Drystone iCOMP – encompasses performance components that represent integer math, floating math, graphics and video STREAM - measures sustainable memory bandwidth and the corresponding computation rate for simple vector kernels. It is similar to a number of applications - streaming data, such as video editing, format conversion of audio and video, and encryption primitives. EEMBC

Click to edit Master title style Development Tools Support OS’s Footprint Performance Real Time? Libraries Services IDE Device Drivers Compilers Processor Specific Libraries HW/SW Debugging Tools Performance Tools

Click to edit Master title style Choices of Microprocessors A wide range of microprocessors and/or microcontrollers are available Processors vary in word size/bus width internal memory and peripherals Timers, I/O ports, DMA channels, etc. supported external memory Power/Performance Many sizes and configurations available, with obvious cost and performance tradeoffs Feature Set directed to specific applications Math co-processors Streaming data

Click to edit Master title style Many, Many, Many Dozens of companies who make processors Hundreds of different processors architectures x86, Mips, ARM, X-Scale, Itanium, 8052, DSP, 3d Graphics Engines Thousands of different Processors 8088, 8086, 80186, 80286, Pentium ….. Arm710, Arm720, Arm920, Arm 922, Arm1020 ….. X-Scale – PXA255, PXA262, PXA265, PXA272 ….. Itanium – Itanium1, Itanium2 900MHz, Itanium2 1.3 GHz ….. MIPS324K, MIPS324KE, MIPS645K, ….. PIC16F876A, PIC16F873A, PIC16C94, ….. DSP – 56000, 56200, 56F8300, TMS320, ….. 3D graphics engines – ATI Radeon9600, NVidia GEForce 6800 …..

Backup

Click to edit Master title style Interview Questions Why do you want to work for Erilyn Engineering? What do you expect from us? (looking for mutual benefit) We have lots of work to do here. What if your assignment takes you longer to complete than expected? What will you do? (looking for good communication and commitment to task) Can you give me an example of when you worked nights and weekends? (looking for commitment to task) What if we have a critical deliverable when your wife is having a Birthday? (looking for balancing priorities) Have you ever worked in a team environment? If so, give me a good example of how a team should work together? How about a bad example? (looking for positive team player) What do you do if someone on the team is not completing their assignments (looking for good communication, ability to take on responsibility, looking for proactive solutions to problems – do not hide from problems – confront them)

Click to edit Master title style Interview Questions Write a short C program with a global variable x and a local int variable array y of 4 values int x; myfunc (void) { int y[4]; } What is the difference between x and y? Scope Where are x and y physically located? X in data mem, y on stack Add pointer to int z and have it point to y; Int *z; Z = &y; If I add the function z++, what does it mean? z points to y[1]

Click to edit Master title style Interview Questions Give truth table for a 2 input NAND gate Give truth table for 2 input XOR gate Construct an XOR function using NAND gates