Maximum bandwidth serial interface

Flowcharts of InChar and OutChar using busy-wait synchronization. Polling before writing data is an efficient way to perform output.

Be careful when using Port C to be friendly; the pins PC3-PC0 are used by the debugger and you should not modify their configurations.

I 2 C1SCL. I 2 C1SDA. I 2 C0SCL. I 2 C0SDA. I 2 C3SCL. I 2 C3SDA. I 2 C2SCL. I 2 C2SDA. PA0 and PA1 are hardwired to the serial port. Program Let n be an unsigned bit integer. We will also need an index, i. To convert this string of 3 decimal digits into binary we can simply calculate.

This second method could be used for converting any string of known and fixed length. If Data were a string of 9 decimal digits we could put the above function into a loop. If the length were variable, we can replace the for-loop with a while-loop. If Data were a variable length string of ASCII characters terminated with a null character 0 , we could convert it to binary using a while loop, as shown in Program A pointer to the string is passed using call by reference.

In the assembly version, the pointer R0 is incremented as the string is parsed. R1 contains the local variable n , R2 contains the data from the string, and R3 contains the constant The example, shown in Program All input characters are echoed. If there is a minus sign, then set a flag. Next use our unsigned conversion routine to process the rest of the ASCII characters and generate the unsigned number, n.

If the flag was previously set, we can negate the value n. To convert an unsigned integer into a fixed length string of ASCII characters, we could use the integer divide. Assume n is an unsigned integer less than or equal to In Program The first program stores the conversion in an array and the second function outputs the conversion to the UART. Sometimes we represent noninteger values using integers.

For example the system could store the value 1. In this example, the voltage ranges from 0. If the system wishes to display those values in volts, we simply add a decimal point to the output while converting, as shown in Program To convert an unsigned integer into a variable length string of ASCII characters, we convert the digits in reverse order, and then switch them. Print unsigned bit decimal number to an output device. Example Design a function that outputs a bit unsigned integer.

Solution: We will solve this iteratively. The iterative solution has three phases: initialization, creation of digits, and output of the ASCII characters.

The digits are created from the remainders occurring by dividing the input, n by To get all the digits we divide by 10 until the quotient is 0. Because the digits are created in the opposite order, each digit will be saved in a buffer during the creation phase and retrieved from the buffer during the output stage.

The counter is needed so the output stage knows how many digits are in the buffer. Successive refinement method for the iterative solution. The iteration solution requires two loops; the first loop determines the digits in opposite order, and the second loop outputs the digits in proper order.

Iterative implementation of output decimal. Animation html5 : two microcontrollers connected via serial port, communicating in full duplex, both main programs use busy wait, data collected on A is passed to B, data collected on B is passed to A. A network is a collection of interfaces that share a physical medium and a data protocol.

A network allows software tasks in one computer to communicate and synchronize with software tasks running on another computer. For an embedded system, the network provides a means for distributed computing. The topology of a network defines how the components are interconnected.

Examples topologies include rings, buses and multi-hop. The advantage of this ring network is low cost and can be implemented on any microcontroller with a serial port. Notice that the microcontrollers need not be the same type or speed.

A simple ring network with three nodes, linked using the serial ports. In this chapter we presented the hardware and software interfaces for the UART channel. In this section, we will build on those ideas and introduce the concepts of networks by investigating a couple of simple networks. In particular, we will use the UART channel to connect multiple microcontrollers together, creating a network.

A communication network includes both the physical channel hardware and the logical procedures software that allow users or software processes to communicate with each other. The network provides the transfer of information as well as the mechanisms for process synchronization.

When faced with a complex problem, one could develop a solution on one powerful and centralized computer system. Alternatively a distributed solution could be employed using multiple computers connected by a network. The processing elements in Figure Distributed processing places input, output and processing at multiple locations connected together with a network. There are many reasons to consider a distributed solution network over a centralized solution.

Often multiple simple microcontrollers can provide a higher performance at lower cost compared to one computer powerful enough to run the entire system. For real-time operation there may not be enough time to allow communication a remote sensor and a central computer.

Another advantage of distributed system is improved debugging. For example, we could use one node in a network to monitor and debug the others. Often, we do not know the level of complexity of our problem at design time.

Similarly, over time the complexity may increase or decrease. A distributed system can often be deployed that can be scaled. For example, as the complexity increases more nodes can be added, and if the complexity were to decrease nodes could be removed. Develop a communication network between two LaunchPads. There will be five questions and three responses. The information is encoded as colors on the LED. The five questions are. Red: Are you there in your office?

Yellow: Are you happy? Green: Are you hungry, want to have lunch? Blue: Are you thirsty, want to meet for a beverage? LightBlue: Shall I come to your office to talk? White: Yes. Purple: Maybe. Dark: No.

Chat Tool Protocol. While selecting the message the LED displays the message to be sent. The driver from Program Chat Tool Program walk through. Logic Analyzer used as a Network Sniffer. Demonstration of the Chat Tool. Microcontrollers employ multiple approaches to communicate synchronously with peripheral devices and other microcontrollers.

The synchronous serial interface SSI system can operate as a master or as a slave. The channel can have one master and one slave, or it can have one master and multiple slaves. With multiple slaves, the configuration can be a star centralized master connected to each slave , or a ring each node has one receiver and one transmitter, where the nodes are connected in a circle. The master initiates all data communication. The interface uses one of the synchronous serial ports on the TM4C The fundamental difference between a UART, which implements an asynchronous protocol, and a SSI, which implements a synchronous protocol, is the manner in which the clock is implemented.

Two devices communicating with asynchronous serial interfaces UART operate at the same frequency baud rate but have two separate clocks. With a UART protocol, the clock signal is not included in the interface cable between devices. Two devices communicating with synchronous serial interfaces SSI operate from the same clock synchronized. With a SSI protocol, the clock signal is included in the interface cable between devices.

Typically, the master device creates the clock, and the slave device s uses the clock to latch the data in or out. The slave select SSI0Fss is a negative logic control signal from master to slave signal signifying the channel is active. In order to work properly, the transmitting device uses one edge of the clock to change its output, and the receiving device uses the other edge to accept the data.

Notice the pin PA4 is not used, which would have allowed for receiving data from the device. The Nokia interface does not use PA4. Be careful, there are multiple displays for sale on the market with the same LCD but different pin locations for the signals. Please look on your actual display for the pin name and not the pin number. Be careful when connecting the backlight, at 3. If you want a dimmer back light connect 3. For more information about SSI, see Section 8.

Learn how to program the UART. Build a distributed system by connecting two systems together. Introduction to Serial Communication Synchronization Mechanisms Video In serial interfaces you need to make sure that clock rate and bandwith do match changing clock rate does not automatically changes bandwith Otherwise it could happen that your routing protocol does not take into account a link or sets the best route through the wrong link, because of bad settings in bandwith parameter.

In order to understand clock rate we first need to understand how the cabling works on routers. The DCE side of the cable is the side that sets the speed of the link also known as clocking. The DTE side of the cable is where the communications terminate ie: your router terminates the connection from the service provider. From a configuration point of view the DCE side of the cable is able to use the clock rate command to set the speed of the line. If the command is not used the interface will run at the maximum speed supported by the interface.

If no bandwidth command has been configured on the interface, Routing protocols and QOS will assume the line is running at the maximum speed supported by the interface which can result in incorrect routing and incorrect prioritization of packets.

Learn more. Maximum potential speed for serial port rs [closed] Ask Question. Asked 9 years, 2 months ago. Active 11 months ago. Viewed 49k times. Improve this question. Add a comment. Active Oldest Votes. Improve this answer. Hans Passant Hans Passant k gold badges silver badges bronze badges.

The maximum speed is limited by the specs of the UART hardware. So if the maximum speed is 1. I guess bios chip performs division of frequency. Can i somehow configure the hardware so that UART gets more than 1. I'm pretty sure the clocking in UART is: the receiver measures the pulse time of a bit and "synchronizes" to it. So while there's no "clock" signal sent in another line, it is self-syncing. The very first bit is a throwaway used to measure the rate.

There is no "negotiation" phase like there is in modems. The receiver either can, or can't, recognize the start bit. The sender has no way to tell if the send data is accepted, unlike a modem which negotiates a two-day communication starting at the lowest speed and working up.

All embedded UARTs I'm familiar with require the receiver to have the expected baud rate programmed into it before reception begins. There is no requirement that the first data bit is different from the start bit, so using the start bit as a synchronization device seems very difficult.