Single conductor bidirectional communication link

Abstract

A driver is coupled to a single conductor wire that may be electromagnetically shielded to drive serial signals on the wire, and a receiver is coupled to the wire and to the driver to receive serial signals from the wire at the same time.

1 . An apparatus comprising:
 a driver operable to drive serial signals on to a single line; and   a receiver coupled to the line and coupled to the driver, the receiver operable to receive serial signals from the line at the same time that the driver is driving serial signals on to the line.   
   
   
       2 . The apparatus of  claim 1  wherein:
 the driver is operable to drive serial digital signals on to the line; and   the receiver is operable to receive serial digital signals from the line.   
   
   
       3 . The apparatus of  claim 1  wherein the line comprises an electromagnetically shielded wire. 
   
   
       4 . The apparatus of  claim 3  wherein the electromagnetically shielded wire comprises a coaxial cable. 
   
   
       5 . An apparatus comprising:
 a driver coupled to a single conductor wire that is electromagnetically shielded to drive serial signals on the wire; and   a receiver coupled to the wire and coupled to the driver to receive serial signals from the wire at the same time that the driver is driving serial signals on to the wire.   
   
   
       6 . The apparatus of  claim 5  wherein the wire comprises a coaxial cable. 
   
   
       7 . The apparatus of  claim 5 , further comprising:
 a first UART coupled to the driver to convert parallel digital signals into serial digital signals to be received by the driver, the driver to drive the serial digital signals on the wire; and   a second UART coupled to the receiver to convert serial digital signals from the receiver into parallel digital signals based on serial digital signals received by the receiver from the wire.   
   
   
       8 . A system comprising:
 a first module;   a second module; and   a single conductor wire that is electromagnetically shielded coupled between the first module and the second module to couple serial signals from the first module to the second module and to couple serial signals from the second module to the first module to support bidirectional communication between the first module and the second module.   
   
   
       9 . The system of  claim 8  wherein:
 the first module is formed in a first integrated circuit chip; and   the second module is formed in a second integrated circuit chip.   
   
   
       10 . The system of  claim 8  wherein the first module and the second module each comprise one of a transmit power amplifier module, a transmit RF module, a transmit IF module, a receiver RF module, a receiver IF module, a digital and mixed-signal module, a synthesizer module, and a control module in a radio unit in a macro base station. 
   
   
       11 . The system of  claim 8  wherein:
 the first module comprises a keyboard; and   the second module comprises a computer.   
   
   
       12 . The system of  claim 8  wherein each of the first module and the second module comprise:
 a driver coupled to the wire to drive serial signals on the wire, the driver having a low output impedance and comprising a linear amplifier or a digital gate, the digital gate comprising a buffer or an inverter;   a first universal asynchronous receiver-transmitter (UART) coupled to the driver to convert parallel digital signals into serial digital signals to be received by the driver, the driver to drive the serial digital signals on the wire;   a receiver coupled to the wire and the driver to receive serial signals from the wire, the receiver comprising a differential amplifier or a comparator having an inverting input and an non-inverting input, the inverting input being coupled to an output of the driver through a voltage divider to receive a reference voltage, and the non-inverting input being coupled to the wire; and   a second UART coupled to the receiver to convert serial digital signals from the receiver into parallel digital signals based on serial digital signals received by the receiver from the wire.   
   
   
       13 . The system of  claim 12  wherein:
 the first UART is coupled to receive a parallel interrupt request and to couple a serial interrupt request to the driver in response to the parallel interrupt request; and   the second UART is coupled to receive a serial interrupt request from the receiver and to transmit a parallel interrupt request in response to the serial interrupt request.   
   
   
       14 . The system of  claim 12  wherein the second UART is insensitive to glitches. 
   
   
       15 . The system of  claim 12 , further comprising a glitch filter coupled between the receiver and the second UART, the glitch filter comprising a digital glitch filter or an analog low-pass filter comprising a capacitor and a resistor to reduce glitches. 
   
   
       16 . The system of  claim 8  wherein the wire comprises a coaxial cable. 
   
   
       17 . A method comprising:
 driving first serial signals on to a single line from a module; and   receiving second serial signals from the line in the module at the same time.   
   
   
       18 . The method of  claim 17  wherein:
 receiving second serial signals further comprises receiving serial digital signals comprising a plurality of bits from the line, each bit in the serial digital signals comprising a first edge transition; and   further comprising sampling the serial digital signals according to each first edge transition.   
   
   
       19 . The method of  claim 18  wherein:
 each bit in the serial digital signals comprises a negative edge transition; and   further comprising:
 generating a delayed signal from the serial digital signals that is delayed by one half of a period of each bit in the serial digital signals; 
 inverting the delayed signal to generate positive edge transitions from negative edge transitions in the delayed signal; and 
 sampling the serial digital signals in a flip-flop at each one of the positive edge transitions that are coupled to a clock input of the flip-flop. 
   
   
   
       20 . The method of  claim 17 , further comprising:
 converting parallel digital signals into serial digital signals to be received by a driver in the module in a first UART coupled to the driver in the module, the driver to drive the serial digital signals on to the line; and   converting serial digital signals from a receiver in the module into parallel digital signals based on serial digital signals received by the receiver from the line in a second UART coupled to the receiver in the module.   
   
   
       21 . The method of  claim 17  wherein:
 driving first serial signals further comprises driving serial control signals, serial status signals, and serial interrupt signals on to the line from the module; and   receiving second serial signals further comprises receiving serial control signals, serial status signals, and serial interrupt signals from the line in the module.   
   
   
       22 . The method of  claim 17  wherein driving first serial signals further comprises driving the first serial signals on to a single conductor wire that is electromagnetically shielded from the module. 
   
   
       23 . The method of  claim 17  wherein:
 driving first serial signals further comprises driving the first serial signals from a first module; and   receiving second serial signals further comprises receiving the second serial signals from a second module coupled to the line, the second module being a slave and the first module being a master with respect to the second module.   
   
   
       24 . The method of  claim 17  wherein:
 driving first serial signals further comprises driving the first serial signals from a first module; and   receiving second serial signals further comprises receiving the second serial signals from a second module coupled to the line, the second module being a peer with respect to the first module.   
   
   
       25 . A system comprising:
 a keyboard;   a computer; and   a single conductor wire that is electromagnetically shielded coupled between the keyboard and the computer to couple serial signals from the keyboard to the computer and to couple serial signals from the computer to the keyboard to support bidirectional communication between the keyboard and the computer.   
   
   
       26 . The system of  claim 25  wherein each of the keyboard and the computer are coupled to drive serial control signals, serial status signals, and serial interrupt signals on to the wire and to receive serial control signals, serial status signals, and serial interrupt signals from the wire. 
   
   
       27 . The system of  claim 25  wherein the wire comprises a coaxial cable.