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Using the MSP-EXP430FG4618 Development Tool and the MSP430FG4618 device use the USCI module in UART mode connected to a PC’s I/O console. When the connection is established, the characters sequence writed at the console through the keyboard will be visualized on the console.

Laboratory communications: lab1 - echo test using the uart mode of the usci module


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.


This laboratory explores the USCI module in UART mode that will be connected to a Code Composer Essentials (CCE) IO console. When the connection is established, the character sequence written on the keyboard to the console will be displayed again on the console.


This laboratory uses the USCI module in asynchronous mode. The RX interrupt activates the service routine that reads the incoming character and sends it out again to the PC (computer), allowing the instantaneous display (echo) of the written character.

The resources used are:

- USCI module;

- Interrupts;

- IO ports:

- System clock.

With the objective of allowing the generation of two different baud rates, a function has been added that configures the FLL+ and selects the base frequency for the UART. In this example it will be 8 MHz.

Software application organization

The proposed application ( Lab1_Comm.c ) is organized as shown in Figure 1. The main routine performs the necessary hardware configuration. Then, the hardware takes command of the software through the interrupt service routine generated by the reception of a new character.

The initial configuration sets the system clock to a frequency of 8 MHz.

Software application organization

System configuration

Uart configuration

The connection will operate in the following mode:

- Parity disabled;

- LSB first;

- 8-bit data;

- One stop bit.

The module will operate in the following mode:

- Asynchronous;

- SMCLK source clock;

- No Receive erroneous-character interrupt-enable;

- No Receive break character interrupt-enable.

Based on these characteristics the following control registers are configured:

UCA0CTL0 = 0x00; // UCA0CTL0 =//UCPEN|UCPAR|UCMSB|UC7BIT|UCSPB|UCMODEx|UCSYNC| //UCPEN (Parity) = 0b ->Parity disabled //UCPAR (Parity select) = 0b ->Odd parity //UCMSB (MSB first select) = 0b ->LSB first //UC7BIT (Character length) = 0b ->8-bit data //UCSPB (Stop bit select) = 0b ->One stop bit //UCMODEx (USCI mode) = 00b ->UART Mode //UCSYNC = 0b ->Asynchronous modeUCA0CTL1 = 0x81; // UCA0CTL1 =//UCSSELx|UCRXEIE|UCBRKIE|UCDORM|UCTXADDR|UCTXBRK|UCSWRST| //UCSSELx (USCI clock source select) = 10b ->SMCLK //UCRXEIE = 0b ->Erroneous characters rejected //UCBRKIE = 0b ->Received break characters set //UCDORM = 0b ->Not dormant //UCTXADDR = 0b ->Next frame transmitted is data //UCTXBRK = 0b ->Next frame transmitted is no break //UCSWRST = 1b ->normally Set by a PUC

Baud rate generation

The module has an 8 MHz clock source and the objective is to establish a connection at 9600 Baud. It is necessary to select the baud rate generation in oversampling mode:

UCA0BR0 = 0x34; UCA0BR1 = 0x00;//Prescaler = 8MHz/(16 x 9600) = 52 = 0x34 //9600 from 8MHz ->SMCLKUCA0MCTL = 0x11; // UCA0MCTL = UCBRFx | UCBRSx | UCOS16//UCBRFx (1st modulation stage) = 0001b ->Table 19-4 //UCBRSx (2nd modulation stage) = 000b ->Table 19-4 //UCOS16 (Oversampling mode) = 1b ->Enabled

Port configuration

In order to set the external interfaces at the USCI module, it is necessary to configure the I/O ports. Select the USCI peripheral in UART mode following the connections provided on the Experimenter’s board:

P2SEL |= 0x30; // P2.4,P2.5 = USCI_A0 TXD,RXD

Rx interrupt enable

To finish the module configuration, it is necessary to enable the receive interrupts:

IE2 |= UCA0RXIE; // Enable USCI_A0 RX interrupt

Analysis of operation

Once the USCI module is configured in accordance with the previous steps, compile it and run it on the Experimenter’s board.

For the correct operation, there must be a connection between the Experimenter’s board and the PC. If the CCE console is disabled, go to Window>Show View>Console to enable it. If necessary, configure the CCE console options in accordance to the connection details.

Once the program code is running, any character key pressed in the PC keyboard will be displayed on the CCE console.

This example and many others are available on the MSP430 Teaching ROM.

Request this ROM, and our other Teaching Materials here (External Link)

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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
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