It is always necessary to use dedicated probes when using an oscilloscope to measure voltage values or signals. Either 1x, or 10x or even 100x attenuation probes, but this is necessary in order to avoid picking up noise from the ambient and in order to compensate the parasitic elements of regular wires or cables that would influence the result of the measurements.

One of the useful things to have in an electronics laboratory dealing with embedded systems is a generic board that allows you to easily manipulate a few digital IOs, to easily capture and log some analog signals and to easily create some analog waveforms. Whereas there are special dedicated instruments to respond to each of these needs (oscilloscopes, signal generators, etc), a small form factor multipurpose unit is available from National Instruments: the NI USB-6009.

The big disadvantage of a small R1 value is that also the reference voltage on the positive input of the opamp needs to be small, in order to correctly regulate the load current value at 1.5A.

Electronic Loads are devices which may be used to test a great variety of electronic designs. Generally speaking, electronic loads are devices which may be configured to act as artificial loads, sinking a preset current.

The calibration revolves around the MAC (Multiply and Accumulate) unit of the eQADC which is used to implement the following transfer function which transforms a raw (uncalibrated) result into a calibrated one:

eQADC stands for Enhanced Queued Analog-to-Digital Converter, and this is the name of the ADC module integrated in the MCP5510 Family microcontrollers. As a hardware engineer, I was more used to the simple 10bit ADC which are usually found in lower end 8-bit microcontrollers (like the PIC18 series, for instance). The first time I came across a MPC5517 from Freescale, however, I was baffled by the need to calibrate the eQADC module, which would otherwise be affected by large errors.

Rechargeable batteries are becoming more and more common in all areas where regular batteries were used up to now, although the concept of “recharge” has been around for quite some decades (think about the lead acid vehicle batteries). This article will briefly go through the most common of the rechargeable battery types, presenting their characteristics and looking at the recharge method.

Many of the embedded systems developed today need some sort of wireless communication.

This article shows how you may play WAV file created on your PC on an audio embedded system (comprising of a microcontroller, a DAC and a D class amplifier); it will detail the format of WAV files, show how you may extract raw data from them, how you translate it and how you should play it on. PC motherboards have both negative and positive supply voltage, therefore it is relatively easy for them to generate the dual polarity signal required to play a sound in a speaker. But how about audio embedded systems? Their overwhelming majorities (think about the number of mp3 players on the market!) have only positive power supply, so audio data has to be somehow translated to a positive interval.

The National Semiconductor LMX9838 Bluetooth Serial Port module is a fully integrated Bluetooth 2.0 baseband controller, 2.4 GHz radio, crystal, antenna, LDO and discreets; combined to form a complete small form factor (10 mm x 17 mm x 2.0 mm) Bluetooth node. Its PCB footprint, however, is not one of the friendliest in the world. In addition it needs a 4-layer PCB. These were the reasons which determined me to design my own application board for the LMX9838.