Nathaniel (Nat) Ersoz

***** * ********* ****

Woodway, WA 98202

425-***-****

ad30ka@r.postjobfree.com

https://github.com/natersoz/nrf

SUMMARY:

I have an excellent record of project completion. I've worked on a wide array of systems including RF and video circuit design, mixed signal circuit design, digital video hardware, class 3 embedded medical device software.

Alphabet soup of tech: C, Modern C++ (17), Python, GoogleTest & Mocks, Bluetooth LE, ARM Cortex M, SPI, I2C protocols.

ISO/IEC-62304 Software Development Lifecycle fluency.

Completed risk management training, compliant with ISO-14971.

WORK EXPERIENCE:

Impinj Inc., Seattle, WA (4/2017 - Present), Principal Wireless Engineer

Principal Engineer/Individual Contributor to Impinj’s ARM based embedded reader devices.

Full lifecycle development:

1.Pre-silicon bootloader firmware simulation, test definition and verification.

The Impinj Reader Chip embeds a secure bootloader within the mask layer ROM. The firmware modules within the bootloader, its intended interaction with the application firmware, the security model, application upgrade capabilities, were all designed, simulated, and delivered as part of the 1.0 silicon deliverable. Due to the high level of simulation and unit testing, the 1.0 version remains the active bootloader delivered in the embedded Impinj Reader Chip product line.

2.RF and baseband device driver and signal processing implementations.

Working in close collaboration with the systems team I have implemented significant firmware modules of the RFID receiver, transmitter, and dynamic switching algorithms.

3.C SDK delivery to customers.

The Impinj Reader series of devices comes with a POSIX library and Raspberry-Pi based development kit. The SDK provides a turn-key solution for customers to deploy and characterize the reader device. It also serves as a starting point for customer porting efforts.

4.Python ctypes characterization interface. The automated characterization of the reader devices is performed using a python interface, which interoperates through the C SDK using ctypes. I am an individual contributor and maintainer of these interfaces.

5.Testing, testing, testing… (development engineers write a significant portion of the tests):

a.Python based chip simulations for device testing,

b.GoogleTest/Mock based unit testing.

c.Functional automation testing.

d.Firmware based code coverage metrics (using the Bullseye code coverage tools).

e.C and Python SDK code coverage using lcov.

f.Performance automation metrics.

Philips Healthcare, Bothell, WA (4/2015 - 3/2017), Principal Software Engineer

Bluetooth connected toothbrushes, a class 1 medical device.

- IMU real-time streaming via BLE characteristic notifications.

- NFC brush head usage.

- Low power off state < 10 uA.

- Pressure sensor characterization and I2C driver implementation.

- SPI based FLASH file system and on-board session log, accessible via BLE streaming.

i1biometrics, Kirkland, WA (2/2013 - 4/2015), Principal Firmware Engineer

Embedded software technical lead, Impact Sensing Mouthguard and Sideline Receiver.

Technical Contributions:

1.CC1101 frequency hopping radio protocol and device driver implementation (900 MHz ISM band).

2.Slotted Aloha collision-based packet protocol.

3.MSP430 USB implementation of HID and CDC communication.

4.Crash-Test model verification in firmware.

Philips Healthcare, Bothell, WA (4/2010 - 2/2013), Embedded Software Engineer

Senior software engineer on the FR-3 AED (Automated External Defibrillator) program, based on the GreenHills Integrity RTOS.

Technical Contributions:

1.Laerdal QCPR sensor accessory command and data acquisition subsystem.

2.AED Data logging and retrieval subsystems.

3.Defibrillator main control hierarchical state machine (HSM) subsystem.

4.Low level SPI bus accessor subsystem

5.Filesystem performance enhancements.

NeuroVista Corporation, Seattle, WA (1/2008 - 3/2010), Embedded Software Engineer

I was the architect and lead firmware engineer on NeuroVista's Class 3 Implantable Medical Device, the Implantable Telemetry Unit (ITU). The ITU samples ECoG signals and transmits the data over a 2.4 GHz agile radio link. Additionally, the ITU self-manages the battery charge cycle and maintains significant self-test and monitoring functions.

Further Seizure Advisory System Reading:

Do Brain Implants Change Your Identity?

Seizure Prediction Is Possible–Now Let's Make It Practical

Implantable Seizure Advisory System Has Strong Early Results

Seizure Prediction—Conceptualization to First-In-Man Study

Technical Contributions:

1.MSP4301611 based Firmware architect and lead engineer (48 KB FLASH, 10KB RAM)

2.ITU radio based bootloader architecture:

a.Nordic nRF24L01+ radio in Primary receiver mode, conforming to NeuroVista's Telemetry Interface.

b.Console command, control, and maintenance functions capable of reflashing the application space.

c.Self-test and human safety factors based self-monitoring.

3.ITU ECoG Acquisition application:

a.Nordic nRF24L01 radio in primary transmitter mode, conforming to NeuroVista's Telemetry Interface.

b.AD7490 ADC acquisition with innovative low sample jitter.

c.Charging system control and monitoring using the ST L6924D charger and TI bq27500 gas gauging devices.

d.Human factors safety and thermal limits monitoring and self-test measures.

Specific Design Challenges:

●Low power consumption: 5 mA current draw during ECoG Acquisition.

●Low sample jitter: < 50 nS p-p, adjacent sample jitter.

●Nested radio interrupt architecture for SPI DMA based radio transactions.

●Multi-channel radio transmitter requiring independent addressing and frequency agility.

●Class 3 medical device for human implant requiring the highest reliability and robustness standards.

Additional Contributions:

●Helped to create the software development and test life cycle at NeuroVista for both the ITU product as well as the other embedded devices.

●Authored (and co-authored) the ITU Software Requirements Specification, Design Documentation, and Interface Control documents.

●NUnit based embedded device unit testing.

Digeo, Inc ., Kirkland, WA (10/2006 - 1/2008), Systems Engineer

As a systems engineer at Digeo I was the responsible lead for external certification and test activities. These include CableLabs DOCSIS and OpenCable, HDMI, IEEE-1394, Dolby Digital (AC-3), Macrovision and DVD-FLLC. The centerpiece for all Cable product requirements is the CableLabs OpenCable criteria are the Open Cable Host Device and the Unidirectional Cable Product against which Digeo submitted 2 products for certification. The Digeo Unidirectional Cable Product was certified shortly after I left Digeo. During my time at Digeo I helped to assemble the internal testing lab and develop our internal testing protocols.

PortalPlayer, Inc., Kirkland, WA (8/2004 - 5/2006), Senior Principal Engineer

PortalPlayer provides the hardware and software development kit and components for most of the hard disk based portable media players; including the iPod. My role was that of a software development lead within the embedded firmware group.

Technical Contributions:

1.MTP,PTP USB device class development including performance optimization crucial to passing Microsoft's(TM) Plays For Sure(TM) performance and compliance test suite.

2.Optimizations for Janus DRM license track playback, and license storage.

3.Embedded database design and implementation.

4.Multi-core embedded operating system primitives implementation and design.

5.Secure PPI bootloader.

6.Janus, MTP, P4S performance optimization and debug, debug, and more debug...

7.Microsoft WMA decoder performance optimizations, decryption and load balancing.

Myrio/Siemens Corporation, Bothell, WA (3/2000 - 8/2004), Technical Lead, Platform Group

Myrio was a small company of approximately 50 people that has deployed IPTV (MPEG-2 Video over Internet protocol) in over 30 networks both in the US and Europe. Approximately 250,000 set top units were deployed into these networks with Myrio client software installed.

The Platform software development group originally began as Myrio's embedded Linux software development unit and then grew into a more mature and generic platform group; defining the low level interface architecture across a wide range of hardware and software platforms; including Linux, VxWorks, and PowerTV. The goal being a operating system independent and hardware abstracted platform which Myrio's main Java application can reside. I guided this group's progress and delivered a significant amount of software development of my own into our group's effort.

Technical Contributions:

1.The EM84xx MPEG-2 video decoder, MPEG-1 Layer II audio, AC-3 audio decoder.

2.MPEG-2 systems layer over IP processor.

3.POSIX based PVR (Personal Video Recording) library and trick mode video controller.

4.X Video Extension for the TViA Cyberpro 5000, 5300 series graphics devices.

5.The National Semiconductor SC1200 video framebuffer, XFree86 display driver and overlay mixer.

6.X based Video Overlay manager and Java Native Interface class.

7.NTSC Line21 encoding support to the National SC1200 device driver and Tvia X display driver.

8.Geode SCx200 / Sejin keyboard/mouse/remote control driver for Linux.

9.BitBand proprietary VOD server to RTSP client proxy.

10.DVB WSS (Widescreen signaling).

11.Multiple vendor Conditional Access decryption architecture and interface library implementation.

12.Linux Network device driver debugging: natsemi.c and via-rhine.c

Microsoft Corporation, Redmond, WA (2/1998 - 3/2000), SDE, MSTV

The MSTV group's primary charter was to fulfill the ATT/TCI interactive television software contract and deploy Windows CE into a bidirectional cable network using Motorola's DCT-5000 set top box (STB). Our group, Broadcast Services, specialized in multimedia (audio/video) and broadcast data services delivery and presentation.

Technical Contributions:

1.ATI Rage Video capture & overlay.

2.VBI decoding: NABTS and Line 21 codecs.

3.COM interface implementation for the DirectShow architecture (Microsoft's streaming media methodology).

Thomson multimedia Indianapolis, IN (5/1983 - 2/1998)

Senior Member Technical Staff, DOCSIS Cable modem development (8/1997 - 2/1998)

I was the Program Manager (PM) and lead the development effort of Thomson's first DOCSIS cable modem. Thomson was the first to pass CableLabs' certification in 1998. This prestigious achievement was accomplished by our highly competent 10 member technical team and our commitment to perfection in every detail. My own role was that of Program Manager: scoping technical risk, defining work tasks, scheduling deliverables, defining test criteria, maintaining technical documentation, and answering CableLabs' RFP along with subsequent customer interrogations.

Senior Member Technical Staff, Technical Lead FTTC Development (2/1997 - 8/1997)

I successfully lead a team of 5 engineers who wrote both the hardware drivers and protocol stacks for the FTTC (Fiber to the Curb) Network Interface Module. My own work on this project involved writing the receive SAR chip driver and SAR/PDU software API interface and implementation. This project was part of a field demonstration with now defunct Broadband Technologies (BBT).

Senior Member Technical Staff, Technical Lead Core MPEG Development (8/1993 - 2/1997)

I lead a small group of engineers (5) in developing the MPEG System, Video, Audio and Compliance standards for the MMDS product. My individual contribution to this project was to implement the MPEG-2 systems specification (ISO 13818-1) into a Thomson's first silicon Demux IC and device driver interface. I also contributed significantly to upgrading the DSS Video Driver to full MPEG-2 syntax and in testing the video driver for MPEG-2 compliance. Other responsibilities of our MPEG sub-group included integration with partnered encoder and modulator vendors, ATSC Program Guide interface definition, compliance stream specification and tool development.

Member Technical Staff, DirecTV Software Development (3/1992 - 8/1993)

Thomson delivered the first large scale MPEG-2 deployment in 1993 in partnership with Hughes DirecTV. Thomson was the prime contractor for the entire non-satellite related portion of the contract including encoder equipment and encryption technology. Thomson own deliverable was the integrated receiver/decoder (IRD). My own contribution to the IRD software included the embedded software test interface, on screen test menus, integration with factory test automation, data service demultiplexing and serial port and modem device drivers.

Member Technical Staff, Technical Lead Widescreen Television (10/1990 - 3/1992)

Directed the development of the (Widescreen Processor) WSP ASIC - a video trick mode processor which performed picture-in-picture (PIP) style video overlay functions plus other features unique to a 16x9 display.

Member Technical Staff, RF Engineering (5/1983 - 3/1990)

Automated RF alignment, VHF, UHF television front ends.

VHF/UHF front end design.

EDUCATION:

BSEE 1983 Rose-Hulman Institute of Technology

PUBLISHED & PATENTED:

●I have authored or co-authored 18 US patents, most related to digital video.

●Papers written:

"Streaming text to a device context", Borland C++ Developer's Journal, September 1995.

ICCE, Summer, 1992: "Synchronization of Asynchronous Video Signals".

RF Expo, Oct 1988: "Accurate Measurement of Balanced input RF devices".

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