In previous posts, we tested the DC performance of the current sensor board. In this post, we are going to test the current sensor board using a typical toy DC motor as the load.

DC Motors

A DC motor runs from a DC power supply, but the motor currents are …

Intro

We have the most basic elements of the curve tracer working, but we have no way to interface with it other than hooking up the Microchip debugger and downloading array variables.  In this installment, we are going to make the first steps toward getting data to the PC using …

If you have no idea what this is about, go back to the Curve Tracer Requirements Post!

Intro

In previous posts, we have been using the maximum speed 32MHz (16MIPS) oscillator.  This oscillator is prone to some error and we would like to eliminate that error.  In this post, we …

Intro

From this point on, there are various tasks that need to occur deterministically, but not necessarily via an interrupt.  We are going to implement a task manager for this purpose.  For readers, this may be familiar.  We already implemented the task manager for the MSP430 a few weeks ago …

For a project introduction, go back to the first post!

Intro

So, if you are already familiar with the project, you know that I was looking for a quick general-purpose current-to-voltage converter with a low-impedance output.  I received boards this weekend and was able to solder together the module today …

Intro

Up to this point, we have focused on generating signals without necessarily observing those signals.  In this post, we will begin to give the microcontroller the capacity to observe those signals using the Analog-to-Digital Converter (ADC).

ADC Requirements

There are 5 signals to be observed:

1. LD_VOLTAGE_0 - this is the …

Intro

In the initial schematic, you will recall that U1 is an opamp in the differential configuration.  This means that the voltage at the reference input will be the 'center' or '0' voltage of the output.  We decided to place a small RC filter at the input of that opamp …

Intro

In the previous post code-oriented post, we got the DAC generating waveforms of reasonable frequencies.  Unfortunately, a DAC usually has a high output impedance, which will distort our signals if we place it in the wrong circuit.  Fortunately, we can make up for this using the on-board operational amplifiers …

As always, there are some schematic errors.  This is one of the issues with highly integrated ICs, it is so easy to mix up the pins!  Maybe I should stop doing schematic and layout so late at night...

• Vcap should be on pin 20, nothing else.  This error arose from …

Go back to the first post to get some background on this project!

Hardware Patch

Just a couple of notes before we begin coding.  I was using the pinout for the "PIC24F" part on the datasheet whereas I should have been using the "PIC24FJ" part.  This will involve a small …