High−level Instructions
3 − 257
Explanation of example
When the execution condition (trigger) R10 is on, data is read from the FIFO buffer area headed by DT0, and
is stored in DT100.
K100
K101
K100
K101
K102
2
DT0
DT1
DT2
15 0
DT3
(H0204)
DT4
DT6
0
1
2
3
DT7
4▲Writing pointer
K5
K2
K102
K103
4
Reading
pointer
▲DT5
3
DT0
DT1
DT2
15 0
DT3
(H0304)
DT4
▲DT6
0
1
2
3
DT7
4▲
K5
K1
K103
4
DT5
F116 (FIFR) execution
Reading
pointer
moved
DT100
DT100
Number of stored data items
K102
Read out
When the reading pointer is 2
The contents of DT5, which is indicated by the reading pointer 2 are sent to DT100.
After the data has been read, 1 is subtracted to the contents of DT1 (the number of stored data items), and the
reading pointer moves to 3.
(The next time that reading is carried out, the contents of DT100 are sent to DT6, indicated by the 3.)
Description
These instructions read data from the FIFO buffer headed by the area specified by S, and store it in the area
specified by D.
S should specify the beginning of the FIFO buffer defined by the F115 (FIFT) instruction.
Reading of data is done starting from the address specified by the reading pointer when the instruction is
executed.
(n−2)
◆
S
S+1
S+2
15 0
(0)
(n−1)
[D]
Memory size of FIFO buffer
Number of stored data items (words)
Upper address of reading pointer
Data storage area
(n words)
Reading
pointer
・(0), (n−2) and (n−1) are addresses
assigned to the data storage area.
・n is the value specified by the F115 (FIFT)
instruction.
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