Omron CVM1D, Operation Manual

Page: 67 / 468

61
operand and D00010 as the second operand. When this instruction is executed,
the content of CIO 0005 is compared with that of D00010.
It is also possible, however, to use indirect DM and EM addresses as operands
for instructions. If
*
D00100 is specified as the data for a programming instruc-
tion, the asterisk in front of D indicates that it is an indirect address that specifies
another which contains the actual operand data. Likewise, EM indirect addres-
sing is indicated by an asterisk in front of the E,
*
E. When addressed indirectly,
the content of
*
D00100 can be read as either BCD or binary (hexadecimal) data,
depending on the PC Setup for indirect addressing.
If the content of
*
DM (or
*
EM) addresses is defined as BCD in the PC Setup, the
number indicates another DM (or EM) address. If the contents of the
*
DM ad-
dress are not BCD, a
*
DM BCD error will occur, and an error flag, A50003, will be
turned ON. Because only the last four digits of the final address can be specified
in one word, the range of possible BCD numbers is #0000 to #9999, and the
range of DM addresses that can be addressed indirectly is D00000 to D09999.
If the content of D00100 is #0324, then
*
D00100 indicates D00324 as the word
that contains the desired data, and the content of D00324 is used as the operand
in the instruction. The following shows an example of this with the MOVE instruc-
tion.
Word Content
D00099 4C59
D00100 0324
D00101 F35A
D00324 5555
D00325 2506
D00326 D541
5555 moved
to A0090.
Indicates
D00324. Indirect
address
(030)
MOV
*
D00100 A090
If the content of
*
DM addresses is defined as binary in the PC Setup, the number
indicates a internal I/O memory address. The range of possible binary numbers,
$0000 to $FFFF, allows all memory areas, including EM, to be indirectly ad-
dressed.
If, in this case, the content of D00100 is $0324, then
*
D00100 indicates internal
I/O memory address $0324, which is CIO 0804 in the SYSMAC BUS/2 Area, as
the word that contains the desired data, and the content of CIO 0804 is used as
the operand in the instruction. The following example shows this type of indirect
addressing with the MOVE instruction.
Word Content
D00099 4C59
D00100 0200
D00101 F35A
CIO 0512 5555
CIO 0513 2506
CIO 0514 D541
5555 moved
to A090.
Indicates
CIO 0512. Indirect
address
(030)
MOV
*
D00100 A090
DM and EM Areas
Section 3-9