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The state assignment in .NET Add QR Code ISO/IEC18004 in .NET The state assignment

The state assignment use visual .net qr code jis x 0510 integrating touse qr code jis x 0510 in .net RM4SCC In order to QRCode for .NET implement the serial adder, it is necessary to use some device capable of storing the information regarding the presence or absence of a carry. Such a device must have two distinct states, such that each can be assigned to represent a state of the adder.

A number of such devices exist, among which is the delay element, which may simply consist of a D ip- op, to be described subsequently. The capability of the delay element to store information is a result of the fact that it takes a nite amount of time for input signal Y to reach its output y. The length of the delay is usually equal to the interval between two successive clock pulses.

For convenience, we will assume that this delay is one time unit long. The state of the delay element is speci ed by the value of its output y, which may assume either of two values, namely, y = 0 or y = 1. Since the current input value Y of the delay is equal to its next output value, the input value is referred to as the next state of the delay, that is, Y (t) = y(t + 1).

If we assign the states of the delay to those of the adder in such a way that y = 0 is assigned to A and y = 1 to B, the value of y at ti will correspond to the value of the carry generated at ti 1 . The process of assigning the states of a physical device to the states of the serial adder is known as state assignment (or secondary state assignment). The output value y is referred to as the state variable (or secondary variable, to distinguish it from the external primary input variables).

The state assignment is completed by modifying the entries of the state table to correspond to the states of y, in accordance with the selected state assignment. The resulting table is given in Table 9.2, where the next-state and output entries have been separated into two sections.

The entries of the next-state table de ne the necessary state transitions of the adder and thus specify the next value of the output, y(t + 1), of the delay. In addition, since Y (t) = y(t + 1), these entries also specify the input values to the delay at time t required to achieve the. 9.2 The nite-state model basic de nitions Table 9.2 Th visual .net qr barcode e transition and output tables for a serial binary adder Next state Y y 0 1 x1 x2 00 0 0 01 0 1 11 1 1 10 0 1 x1 x2 00 0 1 Output z 01 1 0 11 0 1 10 1 0.

Fig. 9.3 Serial binary adder. x1 x2 Full adder Delay z C0 Y desired stat e transitions. Thus, the next-state part of Table 9.2, which is called the transition table, serves also to specify the required excitation of the delay.

The output part of Table 9.2, which is identical to that of Table 9.1, speci es the output value z for every combination of x1 , x2 , and y.

Consequently, using the map method the following logic equations result: Y = x1 x2 + x1 y + x2 y, z = x1 x2 y + x1 x2 y + x1 x2 y + x1 x2 y. These equations are clearly identical to those obtained in Section 5.4 for the carry and sum functions of the full adder.

The addition is accomplished by retransmitting the carry C0 of the full adder through the delay Y into the full adder s input, as shown in Fig. 9.3.

(Note that a delay whose input is Y is generally referred to as delay Y . ).
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