【文章內(nèi)容簡(jiǎn)介】 so on all is one kind of operation (Operation), we request each kind which the puter carries out to hold the function order the form to write down, this is an instruction. How but can distinguish and carry out these operations? This is by designs the personnel in the design monolithic machinehour to entrust with its mand system to decide. An instruction, is corresponding one kind of elementary operation eo。 The monolithic integrated circuit can carry out the plete instruction, is this monolithic integrated circuit mand system (Iustruction Set), the different type monolithic integrated circuit, its mand system is also different. Uses the monolithic machinehour, beforehand must the question which must solve form a series of instructions. These instructions must be the designation monolithic function recognition 畢業(yè)設(shè)計(jì)外文翻譯 and the execution instruction. The monolithic integrated circuit user for solves the instruction procedure which own question arranges, is called the source program (Source Program). The instruction usually divides into the operation code (Opcode) and the operand (Operand) two major parts. The operation code expressed the puter carries out any operation, namely instruction function。 The operand expressed the participation operation number 39。or39。 operation number is at the address (namely operand deposits place serial number). Because the monolithic integrated circuit is one kind of programmable ponent, recognizes the binary code (0, 1). Wants the monolithic integrated circuit operation, in monolithic integrated circuit system all instructions, all must express by the binary code form. For example, in Intel in Corporation39。s MCS 51 series monolithic integrated circuits, takes out a number from the memory to the CPU in accumulator (in logic unit, participation operation, depositing operation result specialpurpose register) the instructioncode is 74H, the accumulator content adds the number code is 24H immediately, in addition immediately the number code, the accumulator delivers the number to the internal RAM memory code is F6H ~ F7H and so on. These instructions are express the binary machine code with the hexadecimal system. The MCS 51 monolithic integrated circuits word lengths are 8, sometimes, had to plete certain holds affects a byte still not to be able fully to express. Therefore, has the single byte instruction in the mand system, also has the multi bytes instruction. The machine code is by a succession of 0 and 1 is posed, does not have the obvious characteristic, not the good memory, is not easy to understand, is easy to make a mistake. Therefore, straight takes over the use of it to pile the procedure to be extremely difficult. Thus, the people use some to help record the symbol (Mue monic) usually are instruction function English condense replace the operation code, like MCS 51 center numbers transmission monly used MOV (the Move abbreviation), the addition with Add (the Addition abbreviation) took helps records the symbol. Thus, each instruction has the obvious movement characteristic, easy memory and understanding, also is not easy to make a mistake. With helps records the procedure which the symbol piles to be called the assembly language procedure. But, helps records the symbol pilation the procedure to be advantageous for the human to understand, but the monolithic integrated circuit only knows the binary system machine code actually, therefore, in order to let the monolithic function read the assembly language procedure to have again to transform by the binary machine code constitution procedure, this kind of switching process, is called the assembly. The assembly may draw support in manual Zha Biaofa realizes, also may socalled draw support from PC machine to plete through the cross assembler. Once entered the monolithic integrated circuit by the machine code constitution user program, again the start the monolithic integrated circuit, might let it carry out the task which the input routine stipulated. Third section MCU51 CPU and memory Monolithic integrated circuit 8,051 CPU is posed by the logic unit and the controller. First, logic unit The logic unit by pletes binary the arithmetic/Logic operation part ALU is a core, in addition temporary storage device TMP, accumulator ACC, register B, program state symbol register PSW and Boolean processor. Accumulator ACC is eight registers, it is in CPU works the most frequent register. When carries on the arithmetic, the logic operation, accumulator ACC often temporarily stores before the operation an operand (for example addend), after but operates preserves its result (for example algebra and). Register B mainly uses in the multiplication and the division operation. Symbolized register PSW also is eight registers, uses for to deposit the operation result some characteristics, whether there is like carries, borrows and so on. Its each position concrete meaning as follows shows. PSW CY AC FO RS1 RS0 OV P says to the user, what is nicest is following four. 1 161。245。benzene 161。245。position sign CY (PSW 161。245。161。245。7). It expressed operates whether has carries (or borrows). If the operating result has in the highest order carries (addition) or borrows (subtraction), then this is 1, otherwise is 0. 2 161。245。prepares 168。214。 161。245。carries symbolizes AC. Also called partly carries the symbol, it had reflected 畢業(yè)設(shè)計(jì)外文翻譯 two eightdigit numbers operate low four whether has partly carries, namely low four add together (either reduces) whether or not carries (or borrows), like has then AC is 1 condition, otherwise is 0. 3 161。245。coins red soft hail afterglow of the setting sun chronic illness 161。245。OV. Whether the MCS 51 reflections belts sign digit operation result does have the overflow, when has the overflow, this is 1, otherwise is 0. 4 161。245。pels 230。197。 anx