System Integration
From Hardware and Software to a
Complete Embedded System

Our engineers have experience developing custom embedded applications. One example of such a project that we have completed is a vehicle tracking project.

The customer's basic requirements for the project included:

• Always-on cellular modem connection - field service calls are very expensive, thus the ability to reliably perform diagnostics and upgrades remotely is highly cost effective
• Vehicle telemetry acquisition - implemented as a custom daughter card integrating a GPS unit and processing of custom signals from various sensors on the vehicle
• Data logging - Storage of all telemetry on-board so that in case a vehicle goes out of range the data acquired during this period can be transmitted when it comes back into a cellular coverage area.
• Web based interface - Integration with Google Maps to display satellite image of current vehicle location with speed and other telemetry information.

During the development process our engineers designed a customer daughter card implementing the required telemetry functions, along with a Linux device driver to access this information and application software to process this information for transmission and logging. We also worked closely with the customer in the installation and testing of the initial units to monitor and enhance the software to support newer sensor types providing data in different formats, as well as to tweak the custom metal enclosures to handle the extreme heat and dusty conditions these vehicles routinely encounter in the Sonoran desert.

Technologic Systems writes and modifies device drivers for their products and FPGA functionality wherever it makes sense.

For instance, a lot of serial protocols involve the usage of 9-bit data. Since Linux's standard serial API is comprised of sending bytes (8-bits), we modified the framework to allow for passing of 16-bit halfwords to/from userspace. Previously, users of the API were forced to individually examine each byte to be transmitted, change the parity from even or odd to get the desired effect, and then transmit the byte. Not only was this cumbersome, but users also had to pay special attention to FIFO buffering. This was not a very difficult modification and is an example of the mindset our engineers take in trying to improve drivers for embedded system usage.

An example of our experience in integrating diverse hardware and software components is a telephony application which was commissioned by one our customers.

The customer's requirements for the project included:

• caller ID
• tone generation and detection
• digital filtering
• web-based interface

In this project our engineers integrated a customer-designed PCB layout designed to work with one of our boards. In addition, software was written to interface to this new hardware in order to perform telephony functions such caller ID handling, dial tone detection, and a digital filtering for voice activation.