<< Chapter < Page Chapter >> Page >
Using the MSP-EXP430FG4618 Development Tool establish a connection between two MSP430's via the I2C bus. The master receives one byte from the slave. This is the master code. It receives a single byte as soon as a button connected on P1.0 was pressed.

Laboratory communications: lab3 - echo test using i2c

Introduction

The MSP430 contains built-in features for both parallel and serial data communication. This chapter describes the operation of these peripherals, and discusses the protocols, data formats and specific techniques for each type of data communication.

The communication modules available for the MSP430 family of microcontrollers are USART (Universal Synchronous/Asynchronous Receiver/Transmitter), USCI (Universal Serial Communication Interface) and USI (Universal Serial Interface). These provide asynchronous data transmission between the MSP430 and other peripheral devices when configured in UART mode. They also support data transmission synchronized to a clock signal through a serial I/O port in Serial Peripheral Interface (SPI) and Inter Integrated Circuit (I2C) modes.

Overview

This laboratory explores the USCI and USI communication interfaces in I 2 C mode. It uses the two MSP430 devices included on the Experimenter’s board: MSP430FG4618 as the master and the MSP430F2013 as the slave. The master receives a single byte from the slave as soon as a button connected to P1.0 is pressed.

Resources

This laboratory uses the USCI module of the MSP430FG4618 device and the USI module included in the MSP430F2013. Both units operate in I2C mode.

The interrupts on the slave unit are generated exclusively by the USI module. They are:

- START condition in the I2C bus;

- Data reception and transmission.

The interrupts on the master unit are provided by the USCI module. They are:

- Data reception;

- Interrupt on Port1.

The resources used are:

- USCI module;

- USI module;

- Interrupts;

- I/O ports.

Software application organization

The software architecture for this laboratory is shown in Figure 1.

The master task is composed of two interrupt service routines ( Lab3_Comm_1.c ):

- S1 switch service routine used to receive a new frame from the slave;

- USCI module interrupt service routine that reads the data sent by the slave.

Software architecture

For the operational capability of the slave unit based on the USI module, it is necessary to implement a state machine as shown in Figure 2. It is important to note that the states “RX Address” and “RX (N)ACK" are transient states that ensure the USI module is prepared for the next activity.

Slave state machine.

System configuration

Usci_b (master) control registers configuration

The connection via I 2 C bus will operate in the following mode:

- Address slave with 7-bit address;

- Master mode;

- Single master;

- USCI clock source is SMCLK;

The following control registers are configured based on these characteristics:

UCB0CTL0 = 0x0F; //UCB0CTL0 = UCA10 | UCSLA10 | UCMM | Unused | UCMST | UCMODEx | UCSYNC//UCA10 (Own address) = 0b ->Own address (7-bit) //UCSLA10 (Slave address) = 0b ->7-bit slave address //UCMM (Multi-master) = 0b ->Single master //Unused//UCMST (Master mode) = 1b ->Master mode //UCMODEx (USCI mode) = 11b ->I2C Mode //UCSYNC (Synchronous mode enable) = 1b ->SynchronousUCB0CTL1 = 0x81;//UCB0CTL1 = UCSSELx | Unused | UCTR | UCTXNACK | UCTXSTP | UCTXSTT | UCSWRST//UCSSELx (USCI clock source select) = 10b ->SMCLK //Unused//UCTR (Transmitter/Receiver) = 0b ->Receiver //UCTXNACK (Transmit a NACK) = 0b ->ACK normally //UCTXSTP (Transmit STOP condition) = 0b ->No STOP //UCTXSTT (Transmit START condition) = 0b ->No START //UCSWRST (Software reset) = 1b ->Enabled

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Teaching and classroom laboratories based on the “ez430” and "experimenter's board" msp430 microcontroller platforms and code composer essentials. OpenStax CNX. May 19, 2009 Download for free at http://cnx.org/content/col10706/1.3
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Teaching and classroom laboratories based on the “ez430” and "experimenter's board" msp430 microcontroller platforms and code composer essentials' conversation and receive update notifications?

Ask