摘要:
The invention relates to an arrangement for running a system bus in a device such as a programmable controller. The arrangement includes a number of card slots interconnected via a system bus with data and control lines, and via address lines. A number of functional units may be plugged into the card slots. One or more of the functional units may be adapted for read and/or write access (e.g., a CPU component), and each functional unit so-configured includes an arbiter capable of managing the system bus. At system startup, one of the arbiters is activated to manage the system bus while the other arbiters remain passive. The functional units may advantageously be plugged into any of the card slots; that is, there is no need to have a particular card slot dedicated to running the system bus.
摘要:
A first CPU and a second CPU form a multi-CPU system which distributes processes related to data input-output and computation. Input-output devices such as an A/D converter and the like are connected to the first CPU through a bus. First and second serial communication circuits stand between the second CPU and the input-output devices of the A/D converter and the like to transmit and receive access demands from the second CPU to the input-output devices of the A/D converter and the like, and the demanded data. Also, the communication arbitration circuit stands between the first serial communication circuit and the first CPU to arbitrate access operations of the first CPU and of the second CPU to the input-output devices of the A/D controller and the like so that these access operations do not overlap.
摘要:
A communication method and apparatus for performing communication between a master device and a plurality of slave devices, prepares, in the master device, the address data of a destination and operation command data to be transmitted to the destination, serially transmits the address data and the operation command data to the plurality of slave devices via the communication path, and executes an operation in accordance with the operation command data in at least one of the slave devices which is designated by the address data. The above operations are all performed in one bus cycle of the master side controller.