Data is transferred in the form of bits between two or more digital devices. There are two methods used to transmit data between digital devices: serial transmission and parallel transmission. Serial data transmission sends data bits one after another over a single channel. Parallel data transmission sends multiple data bits.

Serial Communication Protocol Next: Up: Previous: A protocol is an agreement between two parties about how the two parties should behave. A communication protocol is a protocol about how two parties should speak to each other. Serial communication protocols assume that bits are transmitted in series down a single channel. A serial protocol has to address the following issues • How does the receiver know when to start looking for information? • When should the receiver look at the channel for the information bits? • What is the bit order? (MSB or LSB first) • How does the receiver know when the transmission is complete?

The IR link you'll be constructing is an asynchronous serial link and this means that these four issues must be agreed upon by both transmitter and receiver prior to sending any information. In general, serial links transmit data in distinct packets or frames. A frame is a set of bits that are transmitted sequentially by the transmitter. In general the frame consists of four types of bits; a start bit, data bits, parity bits, and stop bits.

The start bit is used to signal the beginning of a frame. Heroes 6 Shades Of Darkness Keygen Download Safe on this page. The stop bit is used to signal the end of a frame. The data is contained in the data bits and the parity bit is an extra bit that is often used to detect transmission errors. In this lab, you'll use the MicroStamp11 to transmit a frame that consists of only start, data, and stop bits.

You won't be using parity checking to detect transmission errors. In many serial protocols, the issue of how to detect the start of a transmitted frame uses a special bit known as a start bit. Both transmitter and receiver assume that the channel is initially idle (i.e. Zero volt logical level). The beginning of a frame is then signalled by setting the channel high for a specified length of time and then setting it low again.

Transmission of data bits usually commences a specified interval of time after the falling edge of the start bit. The issue of 'when' to look for data bits in the frame must be agreed upon prior to establishing the link. Asynchronous serial protocols usually require that information bits be transmitted at regular time intervals. For instance if we have a 2400 kbaud modem, then both receiver and transmitter know that they should look for information bits arriving at a rate of 2400 thousand bits per second. One possible way of formulating the protocol is to require that the first data bit occur a fixed time interval after the falling edge of the start bit. As a concrete example, let's assume that the data bits are always an integral multiple of 10 microseconds after the falling edge of the start bit.