Digital control circuit for serial UART transmissions
View Patent ↗A digital control circuit enables/disables the feedback of serial transmissions of an UART receive signal when the G-LINK output port is short circuited in a particular operational mode. In a conventional operational mode, the digital control circuit monitors the state of the UART's Tx output and during an UART transmission, the Rx line normally is used for statistics feedback to set to a high state and eliminate unnecessary or unwarranted UART interrupts generated by the G-LINK circuit. The digital control circuit thus enables the G-LINK signal feedback to the UART when required, thereby maintaining a functionality to identify the unit's operational mode and allows the serial ports of the G-LINK to be configured and utilized during conventional operational modes.
1. A circuit arrangement comprising:
a first circuit having an output line and an input line;
a second circuit having an input line for receiving signals from the output line of the first circuit, and an output line for transmitting signals to the input line of the first circuit;
a control circuit having input lines for receiving the signals from the output lines of the first and second circuits, the control circuit inhibiting the signals transmitted from the output line of the second circuit to the input line of the first circuit when the first circuit is transmitting signals to the input line of the second circuit and thereby preventing the second circuit from re-transmitting the signals received from the first circuit back to the first circuit and further preventing the first circuit from generating an interrupt signal; and
wherein the circuit arrangement is included in a television receiver.
2. The circuit arrangement of claim 1 , wherein the control circuit keeps the input line of the first circuit at a high state when the first circuit is transmitting signals to the input line of the second circuit.
3. The circuit arrangement of claim 1 wherein the first circuit is a selected one of a Universal Asynchronous Receiver/Transmitter (UART) and a Universal Synchronous/Asynchronous Receiver/Transmitter (USART).
4. The circuit arrangement of claim 3 , wherein the second circuit is a G-Link circuit.
5. The circuit arrangement of claim 1 , wherein the second circuit further comprises a bi-directional line.
6. The circuit arrangement of claim 5 , wherein short-circuiting the bi-directional line initiates a demonstration mode.
7. The circuit arrangement of claim 6 wherein the shorting circuiting is a short circuit to ground.
8. The circuit arrangement of claim 1 wherein the control circuit inhibits the signals transmitted from the output line of the second circuit to the input line of the first circuit when the first circuit is transmitting signals to the input line of the second circuit during a first mode of operation and allows the second circuit to transmit signals to the first circuit during a second mode of operation.
9. The circuit arrangement of claim 1 , wherein signals transmitted from the output line of the first circuit control an external pager module through the second circuit for connecting to a pager service.
10. The circuit arrangement of claim 1 , wherein the second circuit further comprises a second input line for receiving IR signals transmitted from an IR source and a second output line for transmitting the IR signals for remotely controlling an external device.
11. The circuit arrangement of claim 1 , wherein the second circuit provides feedback between the output line of the first circuit and the input line of the first circuit.
12. The circuit arrangement of claim 1 wherein the control circuit inhibits the signals transmitted from the output line of the second circuit to the input line of the first circuit according to a mode of operation.
13. a method for controlling communication from a serial interface circuit to a receiver-transmitter circuit in a system under control of a CPU and an operating system, the method comprising the steps of: detecting a mode of operation of the system; when the mode is a first mode, allowing the serial interface circuit to transmit signals to the receiver-transmitter circuit wherein the serial interface circuit corn rises a bi-directional line; and when the mode is a second mode, detecting whether the receiver-transmitter circuit is transmitting signals to the serial interface circuit, and when the receiver-transmitter circuit is transmitting signals to the serial interface circuit, prohibiting the serial interface circuit from re-transmitting the signals received from the receiver-transmitter circuit back to the receiver-transmitter circuit and thereby preventing the receiver-transmitter circuit from generating an interrupt signal; and wherein the method is performed in a television receiver.
14. The method of claim 13 wherein the receiver-transmitter circuit is a selected one of a Universal Asynchronous Receiver/Transmitter (UART) and a Universal Synchronous/Asynchronous Receiver/Transmitter (USART).
15. The method of claim 13 , wherein the serial interface circuit is a G-Link circuit.
16. The method of claim 13 , wherein short-circuiting the bi-directional line initiates a demonstration mode.
17. the method of claim 16 , wherein the shorting circuiting is a short circuit to ground.
18. a circuit arrangement comprising: a first circuit having an output line and an input line; a second circuit having an input line for receiving signals from the output line of the first circuit, and an output line for transmitting signals to the input line of the first circuit, the second circuit further comprising a bi-directional line; and a control circuit having input lines for receiving the signals from the output lines of the first and second circuits, the control circuit inhibiting the signals transmitted from the output line of the second circuit to the input line of the first circuit when the first circuit is transmitting signals to the input line of the second circuit and thereby preventing the second circuit from re-transmitting the signals received from the first circuit back to the first circuit and further preventing the first circuit from generating an interrupt signal; and wherein the circuit arrangement is included in a television receiver.
19. The circuit arrangement of claim 18 , wherein short-circuiting the bi-directional line Initiates a demonstration mode.
20. The circuit arrangement of claim 18 , wherein the first circuit is one of a Universal Asynchronous Receiver/Transmitter (UART) and a Universal Synchronous/Asynchronous Receiver/Transmitter (USART).