MSP430 Tutorial – Understand your Hardware
It is a good idea to understand a little bit about the hardware that is built around the microcontroller. You should understand the hardware even before you are going to start programming the board. If yo are not very comfirtable with hardware, spend some time with your hardware engineer, who will explain you about the circuit. But, in reality it does not take much of your time to understand about the hardware.
In a small microcontroller like MSP430, you need to look at the IO pins, any Serial port or and Analog to Digital converter pins. As a quick understanding of with example let us a look at the Schematics below. This Schematics is from Microcontroller shop.
The Input Output Pins and the LED
Take a look at the LEDs that are connected to the MSP430F169 microcontrller – one of the popular processors in the MSP430 series. The port Pin P6.0 in this schematics has LED ( Light Emitting Diode) connected to it. If the Port pin P6.0 is at high or at voltage 3.3, there will no voltage drop accross the LED and the resistor R13. The LED will not glow. If the port Pin P6.0 is at low or voltage 0, there is 3.3V drop accross the LED and the resitor R13. In that case the LED will glow. MSP430F149 have 6 IO ports that can be used as general purpose Input / Output pins. We have connected one them to the LED. We also have connected a push button at port pin P6.1.
The Connection with Emulator
If you look at the bottom left side of the Schematics, there is a 14 Pin JTAG connector. This connector connects to the emulator using a 14 Pin IDC connector. Notice that your hardware board can get powered by the USB FET Emulator. There is no need of an external power supply. You DO need a source of power supply if the board needs to work on its own.
Something more of the hardware
If you see any issue with your hardware, you will have to check two things. The first is the check for the power supply voltages. Your board should get a power supply between 3.0 to 3.3V. If the power supply is good and the board is not working, check the crystall oscillator using a oscilloscope.