Alamode And Raspberry PI

Introduction

1. ATMEGA328P 8bit microcontroller
2. Precision real-time clock (RTC)
3. Micro SD card reader
4. Reset button
5. Standard shield headers

• Why Alamode?
• Setting up Alamode for Raspberry PI
• Behind the scene of Alamode
• Demo Code
• Common Problems
• Why Alamode?

1. Inbuilt high precision real-time clock with an integrated temperature-compensated crystal oscillator.
2. Supports built-in micro SD card reader. You can make use of it to read and write some useful information.
3. One can make use of the alamode analog pins and program with Arduino sensors.
4. Supports all Arduino Uno and standard compatible shields.
5. In build GPS support for the Fastrax UP501 module.
6. Interface with Raspberry PI via I2C, SPI or Serial UART.

Now it’s the time to set up an alamode package. Run the below mentioned command from your terminal. What we are trying to do is, connect to git repository and get the required setup files for alamode. There is a reason why we have to set up the alamode. Coming next you will understand. Once the above command runs successfully, you should be able to see the alamode-setup.tar file which we will have to extract using tar command. Navigate to the alamode setup folder and run the setup program. The setup runs within a second. You will have to restart Raspberry PI to see the changes. Behind the scene of Alamode Before we start discussing the scene of Alamode, there are various configuration changes that I am going to discuss. You don't really have to worry about these configurations as it's all taken care of by the Alamode setup program. As I have mentioned previously, the Alamode's heart is the same Arduino Uno microcontroller. We will see how the Alamode communicates with the Raspberry PI through serial UART. For those of you, who have some experience or understanding in connecting Raspberry PI to Arduino, you wouldn’t be much surprised in the way it works. Still, I am putting together some of the aspects that might help in understanding the way how the Alamode works with Raspberry Pi. We will not get into the details about the board schematics etc. but let us try to understand the high-level things which might be beneficial to you in understanding the reason behind setting up the alamode. Or say you want to know how the Raspberry PI and alamode communicate with each other, you will have to understand the basics about UART (Universal Asynchronous Reception and Transmission). Feel free to have a look into the following link to have some understanding of UART. Note: The alamode supports I2C, SPI or Serial UART when you are interfacing with Raspberry Pi. But it makes use of Raspberry PI’s Serial UART for uploading sketches. Before we dig into the details, let us see how the Raspberry PI supports communication with the external device. Here’s the typical interfacing mechanism that you see in connecting two devices and communicate with each other by sending and transmitting data to and fro using TX and RX connections. The serial interface in Raspberry PI consists of two signals the TX and RX which are used for transmitting and receiving bits. In order to communicate with an external device with serial communication over UART, you will have to connect the TX of Raspberry PI to the RX of the connected device and similarly, the RX of the PI has to be connected to the TX of the connected device such as Arduino. Note: The TX and RX are a part of the GPIO pins in Raspberry PI. It might look very simple, but there is something which we have to understand that is, the Raspberry PI runs with a voltage level of 0 and 3.3V logic levels whereas the Arduino runs with a voltage level of 0 to 5 volts. There is a voltage difference between these two devices and you wouldn’t be able to directly connect the TX and RX of each of these devices. You need an additional circuitry that is the voltage divider or a logical level convertor. However, when you are dealing with I2C communication with Raspberry PI as a master and the connected device such as Arduino as a slave, you don’t need a voltage divider. Let us now see how the alamode makes use of Raspberry PI’s serial UART for communication. Note - The Raspberry PI uses the UART as serial console input/output. We will have to disable in using a console and also in addition to that the Getty, a program that displays login screen has to be disabled too. You don’t really have to do any of these when you are using alamode for Raspberry PI. The reason being, when you are running the Alamode setup, it does everything for you. Edit the /etc/inittab file to disable gitty. You can do that by running the following command. In order to disable gitty, comment on the following line with a ‘#’ sign in front of it.