Microcontroller Basics - How to Create an SPI Connector from the Programmer to the Microcontroller

By now you might have understood the microcontroller concept to some extent and regarding its ports and pins.

Now it’s time to go a little deeper into the subject and investigate the world of programming.

Having said that, before indulging into a program loading procedure into the chip we need to find a proper way to integrate the SPI (Serial Peripheral Interface) connector with the MCU.

However even after this we can’t just push the SPI into the MCU pinouts, can we? Neither can we allow the extended wires from the SPI to directly get inserted into the bread board. This might also cause incorrect wires setting connected with the incorrect pins making bad connections.

Therefore in order to make things absolutely impeccable, we do the procedures over a tiny veroboard wherein we get the required connecting metal pins also called the “header” soldered. These header pins could now be used for connecting with the SPI connector. The connections from this header may be terminated to another parallel header pins which may be used for the breadboard connections.

Thus the above assembly now forms a snug and reliable intermediate connecting platform for the SPI to the MCU.

Uptil now everything looks nice ad perfect, so let’s move on to earn regarding the programmer which is required between your PC and the MCU.

There could a host of companies who make and sell these programmer units, so procuring these shouldn’t be a problem to you, such as Adafruit Industries, USBtinyISP or Sparkfun etc.

A few of these could look entirely different to the conventional types, but basically have everything identical and follow the standard programming rules and may be used as an interface between your PC and the AVR microcontroller.

However make sure of one think, if you are using some other MCU and not an AVR Atmega32, you may have to check for a correspondingly compatible programmer for that particular MCU chip.

It may be observed that quite a few of these programmers employ identical drivers, something tat must be taken care of and we’ll learn more about it in our subsequent chapters.

Connecting your PC with the microcontroller chip is truly basic, and you would be delighted to know how simple the proceedings are required for this. So let’s hit the button right awayJ

Making the above explained SPI interface board is not difficult, it’s all about getting your solder iron working through all the connections across the shown two header rows of pins on a small general purpose board.

The figure above shows the connection details that you would have to follow while interconnecting the wires between the headers.

To make things even simpler, let’s go through the following connection details for the same by referring to the image above:

SPI pin starting from top left goes to the “Master IN, Slave OUT” (MISO)

SPI pin from center left connects with the clock pin (SCK)

SPI pin at the bottom left joins with the Reset. (We’ll learn elaborately about this pin in the following tutorials)

SPI relevant to bottom right hooks up with the GND pin of the MCU, GND refers to the pin which forms the zero supply line or the negative (relative) rail of the supply.

SPI terminating from middle right header links up with “Master Out, Slave IN” (MOSI) pin of the MCU.

SPI coming out of the top right header is wired up with the (+) of the MCU which is quite obviously the Vdd or the positive supply pin of the MCU.

That’s it.

Connect the two connectors as explained and your SPI interface board is ready for the required actions.

For further help you may consult the figure that shown above, your final interface board should look like this after all the wire connections are appropriately done with the help of the above discussion.
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Hi, I`m Sostenes, Electrical Technician and PLC`S Programmer.
Everyday I`m exploring the world of Electrical to find better solution for Automation. I believe everyday can become a Electrician with the right learning materials.
My goal with BLOG is to help you learn Electrical.
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