Omron SYSMAC C Series Operation Manual page 171

Data Exchange with CPU Unit
Four-word Operating Mode
1, 2, 3...
Data
Pointer
Read/Write
Request Bit
PC Write
Completed Bit
Analog Output
Unit Read
Completed Flag
160
Writing Data
1. The CPU Unit uses MOV or another similar instruction to set data in word n
of the allocated I/O words.
2. The CPU Unit sets RAM address of the Analog Output Unit in the leftmost
byte of word n+1 (bits 08 to 15: Read/Write Pointer).
3. The CPU Unit sets bit 00 of word n+1 (Read/Write Request Bit: OFF for read,
ON for write) to 1.
4. The CPU Unit turns ON bit 06 of word n+1 (PC Write Completed Bit).
5. The Analog Output Unit reads data from word n of the allocated I/O words to
the specified RAM address.
6. When the Analog Output Unit reads the data, bit 06 of word n+3 (Analog
Output Unit Read Completed Flag) in the allocated I/O words is turned ON.
7. The CPU Unit verifies that bit 06 of word n+3 is turned ON, then turns OFF bit
06 of word n+1 (PC Write Completed Bit).
8. When bit 06 of word n+1 turns OFF, bit 06 of word n+3 (Analog Output Unit
Read Completed Flag) turns OFF again.
CPU Unit
Allocated
I/O words
Timing Chart
00 to 15
08 to 15
1. Sets data.
2. Sets RAM address b.
3. Specifies read or write.
4. Turns ON the PC Write
Completed Bit.
6. The Analog Output Unit Read
Completed Flag is turned ON.
7. Turns OFF the PC Write
Completed Bit.
8. The Analog Output Unit Read
Completed Flag turns OFF
again.
Writes to
RAM
Section 9-3
Analog Output Unit
Allocated I/O words
5. Reads data.
Address