Omron 3G8F7-CRM21, Руководство пользователя

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58
Communications Cycle Control Procedures
Section 5-2
5-1-4 Command Access Control
5-2 Communications Cycle Control Procedures
5-2-1 Outline of the Communications Cycle
CompoNet communications cycles involve exchanges of I/O data and Events.
The state where only Events are exchanged without any transactions of I/O
data is called the IDLE state (or the state where I/O communications is
stopped and in idle). The state where both I/O data and Events are
exchanged is called the RUN state (or the state where I/O communications is
running.) The phrase "Communications Cycle Operation" is the general term
where the communication is performed in either the IDLE state or the RUN
state.
Operation of the CompoNet Master Board makes the state transition as
illustrated in below. When you execute the command OPEN_SYSTEM or
OPEN_SYSTEMEX, the Board turns from the initial state to the IDLE state,
and after some time it changes to the RUN state automatically. (The IDLE
state is provided for a certain duration after the Board recognize the Slave
Units so that the participation of Slave Units is facilitated.)
Step Operation procedure Access to Shared Memory
1. Set the command. Set the command to notify to the CompoNet Master
Board in the Command Area (PC
→
BD) (0x3200).
2. Notify the command set. In the Interrupt Trigger register (0x0002), set the CMD
flag to 1.
3. Confirm that the
command set has been
notified. In the Interrupt Request Confirmation register (0x0003),
confirm that the CMD flag turns to 0.
4. Wait for a command
acknowledgment (ACK). In the Interrupt Request Indication register (0x0005),
confirm that the CMD_ACK flag turns to 1. (Confirm it by
an interrupt or by polling.)
5. Read the command
response.
In the Command Area (BD
→
PC) (0x3210), the
command response from the CompoNet Master Board is
stored. Read the response.
6. Release the command
acknowledgment
interrupt. In the Interrupt Clear register (0x0006), set the
CMD_ACK flag into 1, and clear the interrupt cause.