Let’s take a quick look at what it takes to read from the ADC inputs of a i.MX28 based embedded system using example C code provided by Technologic Systems. Now, while this can be generically applied to many i.MX28 based embedded systems, we’ll be working with a TS-7680. Right, let’s get started!
Here’s an example program our engineers might find useful. Kris Bahnsen, a long time engineer for Technologic Systems, wrote this simple program to get the voltage input (Vin) on the 8 – 28 VDC power rail on the TS-7670 (Rev. D or later) or TS-7400-V2 (Rev. B or later). Without going into too much detail about implementation of the on-board supervisory microcontroller, there is a register which is used to store various ADC values, including Vin. This example program basically polls this 4 byte register via I2C interface, accounts for the voltage divider (see TS-7670 schematic or TS-7400-V2 schematic), and spits out the Vin value. So, without further ado, here’s the code:
Having access to live data from out in the field is incredibly valuable in making smart, informed decisions about your business. Fleet vehicle and other traveling asset operations benefit greatly from an in-vehicle data logging and tracking solution. The challenge is collecting and sharing this data reliably because of the inherent challenges with a mobile solution. For example, there are additional power supply considerations for a vehicle that is always starting and stopping. When power is unexpectedly cut off from the embedded data logger, there is a high likelihood of filesystem and data corruption. Another consideration is how to transfer the data once you’ve captured it via CAN or GPS. Thankfully, cellular network providers have done a great job at providing an always-available, nationwide service accessible from nearly anywhere. It would make sense to tap into this network using a cellular modem. Then, perhaps when the vehicle returns to a base station, WiFi or Bluetooth connections can be used to share auxiliary, non-real time data. Lastly, you’ll want to consider operating temperature ranges, as the inside a vehicle can easily reach 130 ºF to 170 ºF (54 ºC to 76 ºC) and on the opposite, reach “Ice Road Truckers” cold to -50 ºF (-45 ºC). It’s important to keep these considerations of power, temperature, and connectivity in mind in order to keep all this data safe and sound. The TS-7670 and TS-7680 single board computers are embedded systems which aim to provide reliable, low power, industrial-grade vehicle asset tracking solutions and solve these challenges.