Data bus

• US 6,453,374 B1
• Filed: 03/30/1999
• Issued: 09/17/2002
• Est. Priority Date: 03/30/1999
• Status: Expired due to Term

• Current Assignee: Rockwell Collins, Inc. (Rtx Corporation)
• Original Assignee: Rockwell Collins, Inc. (Rtx Corporation)
• Inventors: Johnson, Douglas R., Dunn, Gregory E., Kotalik, Stephen I., Kovalan, Mark A., Persick, John L., Wiscons, Bryon L.
• Primary Examiner(s): THAI, XUAN MARIAN
• Application Number:
  US09/281,584
• Time in Patent Office: 1,267 Days
• Field of Search: 710/29, 710/60, 710/100, 710/101, 710/107, 326/21, 326/30, 326/86
• US Class Current: 710/100
• CPC Class Codes: G06F 13/4286 using a handshaking protocol, e.g. RS232C link

Abstract

A bus system including a bus user apparatus and a method for communicating via the bus system are disclosed. The bus user apparatus includes means for means for selectively coupling a transmitter to the transmission line according to a protocol of the bus system. The bus system provides bi-directional communication over a single transmission line. The transmitter of the transmitting device is coupled to the transmission line during transmission. Upon completion of transmission, the transmitting device sends a permission to transmit signal to the next transmitting device according to the protocol, and decouples its transmitter from the transmission line. The next transmitting device couples its transmitter to the transmission line and begins transmission of data. Multiple bus users, both transmitters and receivers, are accommodated by the bus system, and bi-directional communication is supported. Further, the data transmission rate may be increased by selectively coupling the transmitter of a receiving device to the transmission line to provide a termination impedance on the transmission line. Higher transmission rates may be accommodated without a termination impedance; if necessary, a termination impedance may be applied. If necessary, the output voltage of the transmitter and the sensitivity of the receiver may be adjusted to accommodate the higher transmission rates. The bus system may also accommodate larger sized words. The bus system is compatible with previously existing systems compliant with an ARINC standard while providing increased capability.

Claims

1. A method for communicating via a bus system, comprising:

transmitting data via a transmission line at a first rate by transmitting data from a transmitting device to a receiving device;

determining whether to transmit data via the transmission line at a second rate;

in the event it is determined to transmit data at a second rate, coupling an impedance to the transmission line whereby a second transmission rate is accommodated; and

transmitting data via the transmission line at a the second rate.

2. A method as claimed in claim 1, the first rate being a lower rate and the second rate being a higher rate.

3. A method as claimed in claim 1, the first rate being a higher rate and the second rate being a lower rate.

4. A method as claimed in claim 1, further comprising the steps of determining whether the signal level resulting from said coupling step is sufficient, and, in the event it is determined that the signal level is not sufficient, modifying the output voltage of the transmitting device such that the signal level is sufficient.

5. A method as claimed in claim 1, further comprising the steps of determining whether the receiving device has a sufficient sensitivity upon execution of said coupling step, and, in the event it is determined that the sensitivity is not sufficient, modifying the sensitivity of the receiving device such that the sensitivity is sufficient.

6. A method as claimed in claim 1, said coupling step including the step of coupling a transmitter of the receiving device to the transmission line whereby the coupled impedance is provided by the transmitter of the receiving device.

7. A method as claim 1, further comprising the steps of, determining whether to transmit a larger sized word, and, in the event it is determined to transmit a larger sized word, transmitting a larger sized word.

8. A method as claimed in claim 1, the coupled impedance being approximately equal to a characteristic impedance of the transmission line.

9. A method as claimed in claim 1, further comprising the steps of, prior to executing said coupling step, determining whether to terminate the transmission line with an appropriate impedance, in the event it is determined to terminate the transmission line with an appropriate impedance, executing said coupling step.