Multipoint link data-transmission control system

• US 4,888,728 A
• Filed: 03/30/1987
• Issued: 12/19/1989
• Est. Priority Date: 03/29/1986
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yamashita, Hiroaki, Nishida, Toshio, Shirakawa, Masakazu
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): RUDOLPH, REBECCA
• Application Number:
  US07/031,576
• Time in Patent Office: 995 Days
• Field of Search: 340/825.06, 340/325.07, 340/825.08, 340/825.16, 870/85, 870/90, 871/7, 871/11, 871/14, 364/200 MS File, 364/900 MS File
• US Class Current: 709/208
• CPC Class Codes: G06F 13/423 with synchronous protocol
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling

Abstract

According to a multipoint link data-transmission control system, a master transmission device delivers message data via a bidirectional transmission path to a plurality of slave transmission devices, the data containing a control field for designating control data for setting or resetting a flag. The transmitting of data from the slave transmission device to the master transmission device is allowed when the flag is set, and is inhibited when the flat is reset. Where the transmitting of data from a faulty slave transmission device is to be inhibited, the master transmission device transmits the data to the faculty slave transmission device, by designating flag reset data to the control field of the message data. As a result, a transmission-enable signal, which is delivered in synchronization with a transmission-timing clock signal, is reset, thereby stopping the transmitting of data from the slave transmission device to the master transmission device.

Claims

1. A multipoint link data-transmission control system having a master transmission device to which a master processor is connected, and a slave transmission device connected via a synchronous bus to said master transmission device, to which a plurality of slave processors are connected, said slave processors transmitting message data to said master transmission device, said slave transmission device comprising:

a receiving section comprising decoding means for decoding message data transmitted from said master transmission device via said synchronous bus;

said receiving section further comprising;

flag means for indicating whether said slave transmission device transmits or not to said master transmission device, in accordance with a decoded output from said decoding means, said flag means connected to said synchronous bus;

a transmission section comprising transmission data storage means for storing a message data to be transmitted to said master transmission device;

said transmission section further comprising,

transmitting means for transmitting the message data stored in said transmission data storage means,

transmission control means for transmitting message data from said transmission data storage means to said transmitting means in accordance with flag data representing the resetting of said flag means during the transmission of the message data from said transmission data storage means, and said transmission control means stopping operation of said transmitting means after detecting that the message data has been sent from said transmission data storage means, said transmission control means being connected to said flag means; and

,

said plurality of slave processors transmit the message data from said transmission data storage means to said master transmission device in accordance with a corresponding time slot assigned to each of said plurality of slave processors.

2. The system according to claim 1, wherein:

said master transmission device has means for inhibiting said slave transmission device so that faulty message data is not transmitted to said master transmission device.

3. The system according to claim 1, wherein:

said master transmission device has means for designating the same message data to all the salve transmission devices of said plurality of slave processors which are operating normally.

4. The system according to claim 1, wherein:

said master transmission device has means for designating a particular message data and for sending a data transmission-disable flag to said transmission control means so that said master transmission device can inhibit a group of slave transmission devices of the same processing function from transmitting their message data to the master transmission device.

5. THe system according to claim 1, wherein:

with the same time slot assigned to said plurality of slave processors, said slave transmission device having a means for delivering delivers to the master transmission device the message data with said slave transmission device'"'"'s own corresponding identification code attached thereto.

6. A system according to claim 1, wherein:

the message data transmitted from the master transmission device contains control information.