MICROPROCESSOR AND MICROCONTROLLER

Detailed explanation-1: -Description: DA adjusts the contents of the Accumulator to correspond to a BCD (Binary Coded Decimal) number after two BCD numbers have been added by the ADD or ADDC instruction. If the carry bit is set or if the value of bits 0-3 exceed 9, 0x06 is added to the accumulator.

Detailed explanation-2: -DA instruction The DA (decimal adjust for addition) instruction in the 8051 is provided to correct the aforementioned problem associated with BCD addition. The mnemonic “DA” has as its only operand the accumulator “A”.

Detailed explanation-3: -An instruction DJNZ reg, label is used to perform a Loop operation. In this instruction, a register is decremented by 1; if it is not zero, then 8051 jumps to the target address referred to by the label. The register is loaded with the counter for the number of repetitions prior to the start of the loop.