MrChips's Blog

Sometimes when I am developing and debugging a system I need to monitor some intermediate result. I do this by sending ASCII text serially to a "dumb terminal" such as HyperTerm. Believe me, I have a PC on my workbench running COMM on MSDOS just for this purpose. I also have a microcontroller...

Now that we have verified that the ADC is configured properly and working, we can connect the LM35 and then look at the numbers. Connect the LM35 to Vcc and GND of the MSP430G2553. Connect Vout from the LM35 to P1.7 (pin-15) of the MSP430G2553. It is educational to look at the math. The LM35...

Now that we have three digits being displayed, what can we do with them? The first project that comes to mind is a digital thermometer. We will use the popular LM35 temperature sensor which outputs an increasing voltage as the temperature rises. The transfer function of the LM35 is a linear...

Now that you have seen how easy it is to interface to a single seven-segment display, let us add multiple digits to the design. In a traditional digital counter design using standard digital ICs, every time you need to add another digit you need to add another counter, latch, decoder/driver...

Ok, it's time to get back into the MSP430 tutorials. In the next few blogs I will present examples on driving seven-segment LEDs followed by interfacing with the popular alphanumeric LCD modules. So let's get coding and debugging a seven-segment LED example. The classic way to drive a common...

I am thinking of possible followups to this blog. Every microcontroller is a useless chunk of silicon if it does not have some form of output such as LEDs, relays, motors, analog voltage, PWM or digital displays. Here are some possible programming exercises: output to seven-segment display...

The TI MSP-EXP430G2 LaunchPad is ok for quick testing of code during program development. Eventually you would like to program the target mcu in-circuit on your protoboard or project PCB. When laying out your PCB make sure you provide programming headers to the programming pins. You only need...

Now has come the time to wrap up our little timer exercise. What we still have to do: Figure out a way to select different timer delays. Find a way to reset the timer. The second problem should be easy enough. In fact, if we do this right we will not need a RESET button. RESET Pin-16 of...

In the previous post the program is set to flash for 10ms every 1 sec. I did this in order to determine the minimum flash duration that would still be very visible. A pulse width of 10ms and a repetition delay of 1 second is highly visible. This gives a duty cycle of 1:100. If you wish, a...

We are getting close to the end of this little exercise, that is, building a simple low power timer. Now we come to the MSP430 low power modes. The current consumption of a microcontroller is directly related to its operating clock frequency. Stopping the CPU clock gives the lowest power mode...

Okay, get out the soldering iron and solder the 32768Hz crystal to the SMD pads provided at pins 18 and 19 of the MSP430G2553 chip. Our goal is to run with the lowest current drain and still keep accurate time. Here is our program modified to use the crystal oscillator. // Timer...

Interrupts can be tricky to program and they function somewhat magically. However, it is a very important feature of embedded microcontroller systems and should be used to its full advantage. Here is a simple example of the interrupt mechanism followed by some explanations. // Timer example...

The MSP430G2553 has everything we need, including an internal clock, in order to make a decent timer. This is the first of two solutions I will present. This chip also has a low frequency, low power crystal oscillator circuit. So if we really want to do this properly we might as well go all...

Let us review the LED flash program with a twist. // Patrol Cruiser Flashing LEDs Example // 2013.04.25 - MrChips #include "io430.h" #define ON 1 #define OFF 0 #define LED1 P1OUT_bit.P0 #define LED2 P1OUT_bit.P6 #define DELAY 10000 void init(void) { // Stop watchdog timer to prevent time...

I had never intended for this to be a tutorial on programming in the C language. There are many excellent tutorials available online. I cannot endorse any particular site but will only provide an example: http://www.cprogramming.com/tutorial/c/lesson1.html However, I will make a few comments...

At this point you should have the IAR EW integrated development environment (IDE) up and running. You are now able to setup, edit, download and verify a program written in C running on the target MSP430 chip. Let us take a break from the coding and look at some of the program elements. P1OUT...

The next step is to insert two delays in order to slow down the LED flash rate. A 16-bit unsigned integer can represent a value from 0 to 65535. While this is sufficient for our simple delay, we will use a 32-bit unsigned integer in case we need a longer delay at some point in the future...

This series of tutorials is in response to a request for a very low power timer with selectable time delays from 1 hour to 24 hours. These tutorials are based on the Texas Instruments MSP430LaunchPad. Some useful links Texas Instruments product page: http://www.ti.com/product/msp430g2553...