Software 4.4 Types of operands Eco Control 667E differentiates between three types of operands which are marked by their size: Ш Bit 1 bit Ш Byte 8 bit Ш Word 16 bit (2 byte) The accumulator in the CPU of Eco Control 667E can be used as a bit, byte or word register. Bit operations are carried out like byte operations, the dif- ference being that only bit 7 of the 8 bit accumulator is evaluated. Byte operations are executed in the same accumulator as bit operations. Word operations use a 16-bit accu whose low byte con- tains the accumulator where bit and byte operations are executed.
Word operations are started by commands who- se last character is a D (not applicable to byte inputs BIxx and byte outputs Boxx). To avoid mistakes we recommend that you do not use different types of operands in operations that belong toge- ther. 48