Multiplexed synchronous/asynchronous data bus
First Claim
1. A master data device employing a data transmission bus including three communications lines for transmitting a first data message from the master data device to a second data device at a first rate of data transfer and for transmitting a second data message from the master data device to the second data device at a second rate of data transfer, each of the two data messages having a plurality of binary bits each bit having either a binary zero state or a binary one state for a period of time which is related to the data transfer rate, the master data device comprising:
- means for applying a first binary state to a first and a second of the three communications lines before and after said first data message;
means for coupling the first data message to said first and second of the three communications lines;
means for applying a second binary state to said first of the three communications lines when the first data message is not being transmitted; and
means for applying the binary bits of the second data message to said third of the three communications lines while said second binary state is applied to said first of the three communications lines.
1 Assignment
0 Petitions
Accused Products
Abstract
A multiplexed synchronous/asynchronous data bus is disclosed in which three bus lines are used to convey bidirectional synchronous data between at least two data devices at a relatively low data rate. Half duplex asynchronous data is applied at a higher data transfer rate to one of the three bus lines when another of the bus lines is held in a logic high state.
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Citations
29 Claims
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1. A master data device employing a data transmission bus including three communications lines for transmitting a first data message from the master data device to a second data device at a first rate of data transfer and for transmitting a second data message from the master data device to the second data device at a second rate of data transfer, each of the two data messages having a plurality of binary bits each bit having either a binary zero state or a binary one state for a period of time which is related to the data transfer rate, the master data device comprising:
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means for applying a first binary state to a first and a second of the three communications lines before and after said first data message; means for coupling the first data message to said first and second of the three communications lines; means for applying a second binary state to said first of the three communications lines when the first data message is not being transmitted; and means for applying the binary bits of the second data message to said third of the three communications lines while said second binary state is applied to said first of the three communications lines. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A slave data device employing a data transmission bus including three communications lines for receiving a first data message transmitted from a master data device at a first rate of data transfer, for receiving a second data message transmitted from the master data device at a second rate of data transfer, and for communicating a third data message to the master data device, each of the three data messages having a plurality of binary bits, each bit having either a binary zero state or a binary one state for a period of time which is related to the data transfer rate, the slave data device comprising:
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means for receiving a first binary state from first and second of the three communications lines before and after said first data message; means for receiving the first data message from said first and second of the three communications lines; means for coupling at the first rate of data transfer the binary bits of the third data message to a third of the three communications lines; means for receiving a second binary state applied to said first of the three communications lines by the master data device for a period of time greater than one bit time of the first rate of data transfer when the first and second data messages are not being received; and means for receiving the binary bits of the second data message from said third of the three communications lines while said second binary state is received from said first of the three communications lines. - View Dependent Claims (11)
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12. A data transmission system including three communications lines for communicating a first data message from a first data device to a second data device at a first rate of data transfer, for communicating a second data message from the first data device to the second data device at a second rate of data transfer, and for communicating a third data message from the second data device to the first data device, each of the three data messages having a plurality of binary bits, each bit having either a binary zero state or a binary one state for a period of time which is related to the data transfer rate, the system comprising:
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means at the first data device for applying a first binary state to a first and a second of the three communications lines before and after said first data message; means at the first data device for coupling the first data message to said first and said second of the three communications lines; means at the second data device for coupling the binary bits of the third data message to a third of the three communications lines; means at the first data device for applying a second binary state to said first of the three communications lines when the first and third data messages are not being communicated; and means for applying the binary bits of the second data message to said third of the three communications lines while said second binary state is applied to said first of the three communications lines. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A portable radiotelephone apparatus employing a data transmission bus including three communications lines for communicating a first data message to a peripheral data device at a first rate of data transfer, for communicating a second data message to the peripheral data device at a second rate of data transfer, and for receiving a third data message from the peripheral data device, each of the three data messages having a plurality of binary bits, each bit having either a binary zero state or a binary one state for a period of time which related to the data transfer rate, the apparatus comprising:
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means for applying a first binary state to a first and a second of the three communications lines before and after said first data message; means for coupling the first data message to said first and said second of the three communications lines; means for receiving the binary bits of the third data message coupled to a third of the three communications lines by the peripheral data device when the first data message and the second data message are not being communicated; means for applying a second binary state to said first of the three communications lines; and means for applying the binary bits of the second data message to said third of the three communications lines while said second binary state is applied to said first of the three communications lines.
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21. A method of data transmission on a data transmission bus, which includes three communications lines for transmitting a first data message from a master data device to a second data device at a first rate of data transfer and for transmitting a second data message from the master data device to the second data device at a second rate of data transfer, each of the two data messages having a plurality of binary bits, each bit having either a binary zero state or a binary one state for a period of time related to the data transfer rate, the method comprising the steps of:
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applying a first binary state to a first and a second of the three communications lines before and after said first data message; coupling the first data message to said first and second of the three communications lines; applying a second binary state to said first of the three communications lines when the first data message is not being transmitted; and applying the binary bits of the second data message to said third of the three communications lines while said second binary state is applied to said first of the three communications lines. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
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Specification