Lab 8: Serial Communication This lab is based on using the Serial Communications module in the MSP430 microcontroller for asynchronous serial communication. In this lab, students will develop a simple transmitter and receiver module in which two microcontrollers will exchange 1 byte messages. The transmitter module will generate three different signals based on the user input from external push buttons. On the receiver side, the microcontroller will trigger different LEDs depending in the received command. Background and Tutorials Serial communications can be divided into two categories, synchronous and asynchronous.

In MSP430 serial communication is. In this example we are going to configure the MSP430 UART to transmit. For developing UART code,MSP430 has Loop Back. The number of data bits is typically 8, but it can be configured for 7 bits as well. Although some UART receivers can use a different number of bits, only 8 or 8 bits are supported by the MSP430. After the data bits stop bits are sent along with an optional parity bit. MSP430 families contain different peripherals capable of UART communications.

The difference is that synchronous serial communication uses a dedicated communication channel to send a clock signal which provides the timing between the transmitter and receiver devices. There are several versions of both synchronous and asynchronous serial communication. Descargar Driver Hp Deskjet D2360 Windows Xp more. The MSP430 microcontroller offers 3 different types of communications using its USCI peripheral including:, and UART. We will use UART the (AKA RS232 and Serial Port) in this lab. Check the and the if interested.

For context, SPI is a simple clock, enable and data (one for half duplex and two for full) interface. As the data is synchronized with a clock, the bandwidth can be very high for this port (approaching 100MHz); however over long distances (a cable of 4 feet for instance) clock skew will accumulate and consequently this interface is not good for long distance transmission, but rather for moving data between chips on a board. Alternatively, the IIC is a single master / multiple slave bus that also uses a clock and so is for across-board communications - and generally not for long distances. Whereas the SPI is fast, the IIC is slower but allows for one master to read and control many slaves. This is done using a wired OR interface with pull up resistors. The UART (the focus of this lab) does not use a clock (asynchronous) but just an agreed upon baud rate that is generally very slow. Although there is no common clock, even with a difference in local clocks of up to 1%, the communications of 10 bits is reliable.

In fact, in a recent UTEP project where data was sent from a chip in a irradiation chamber over 30 feet away, a UART with a 2400 baud rate over a long cable worked well. From a historical perspective, PCs had 2 ports in the 80’s and 90’s: parallel and serial (UART). Parallel ports were often used with printers and serial ports were often used for modems and game controllers for example. The USCI provides the same protocol used in the PC serial port referred to as UART mode.

Today, both PC port types are being replaced with much faster interfaces like USB. However, the simplicity of the serial port ensures it’s use for a very long time in embedded applications. This port is often called UART (Universal Asynchronous Receive and Transmit). The term RS232 is often used interchangeably as well but technically just describes the voltage and connectors and not the signaling. Dream Day Wedding Activation Code Keygen. The term “serial port” is often used but really is just the port.

The USCI configuration allows for a number of options for data transmission and reception in UART mode. In the simplest configuration, ten bits are involved: a start bit (logical 0), the 8 data bits, and a stop bit (logical 1). An example transmission waveform, such as what you might see if you hooked up a logic analyzer to the TX pin, is shown below. Note that the data bits are sent LSB (bit 0) first, and MSB (bit 7) last. Thus, the middle 8 bits in the pulse train below are sent in the order '10110100' in a time domain signal, corresponding to an actual data byte of $2D (%0010 1101), which is an ASCII minus ' - ' sign.