Host modem having a peripheral codec powered by a peripheral bus

• US 6,408,351 B1
• Filed: 03/31/1998
• Issued: 06/18/2002
• Est. Priority Date: 03/31/1998
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Hamdi, Rabah S., Olkkola, Edward E., Dorsey, David Christopher
• Primary Examiner(s): Lee, Thomas
• Assistant Examiner(s): Perveen, Rehana
• Application Number:
  US09/052,815
• Time in Patent Office: 1,540 Days
• Field of Search: 713/322, 713/300, 455/557, 710/63, 710/64
• US Class Current: 710/63
• CPC Class Codes: G06F 13/4068 Electrical coupling
• CPC Class Codes: G06F 3/162 Interface to dedicated audio devices, e.g. audio drivers, interface to CODECs
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A peripheral coder/decoder (codec) that has low power consumption such that the peripheral codec facilitates bus-powered peripheral devices that utilize a codec. One such peripheral device is a modem. In the case of host-based modem, a host computer provides processing capabilities while a bus-powered peripheral device contains circuitry for analog-to-digital and digital-to-analog conversions as well as circuitry for interfacing to a transmission media. The bus-powered peripheral device is coupled to the host computer by a peripheral bus. In one embodiment, the peripheral bus is a Universal Serial Bus (USB) bus and the bus-powered peripheral device is a USB device. By being bus-powered, the bus-powered peripheral device does not require its own separate power source. A method for transmitting data over the peripheral bus using the host-based modem and the bus-powered peripheral device are also disclosed.

Claims

1. A computer system comprising:

a computer including a microprocessor, memory and a bus host controller;

a bus operatively connected to said computer, said bus being controlled by the bus host controller; and

a codec apparatus operatively connected to said computer via said bus, said codec apparatus being completely powered by said bus, wherein said bus is a serial bus, said codec apparatus is a codec modem, and said codec modem comprises a codec for performing analog-to-digital conversions on incoming signals and digital-to-analog conversions on outgoing signals;

a hybrid circuit, said hybrid circuit couples the outgoing signals to a transmission medium and couples incoming signals to the transmission medium;

wherein the serial bus is a USB bus and said codec modem further comprises;

a USB bus interface coupled between the USB bus and said codec and said USB bus interface comprises;

a USB peripheral bus interface that couples to the USB bus and interacts with the serial bus host controller to transmit data packets between said computer and said codec modem;

a transmit buffer that temporarily stores data to be transmitted by said codec modem over the transmission medium;

a receiver buffer that temporarily stores data received by said codec modem over the transmission medium;

a buffer management and control unit, said buffer management and control unit operates to manages said transmit buffer and said receive buffer and to control overall operation of said USB bus interface;

a power manager, said power manager manages the power consumption of said modem codec based on a mode of the USB bus; and

a remote wakeup unit, said remote wakeup unit monitors external signals and notifies said buffer management and control logic unit at least when a wakeup of the USB bus and/or said modem codec is needed.

2. A computer system as recited in claim 1, wherein the notification provided by said remote wakeup unit is further used to wakeup said computer.

3. A computer system as recited in claim 1, wherein said USB bus interface further comprises:

a output control register, said output control register is used to inform at least one of said codec and said hybrid circuit to enter or leave a reduced-power mode.

4. A computer system as recited in claim 3, wherein said codec comprises:

a receive path including at least an analog-to-digital converter that performs Sigma-Delta demodulation; and

a transmit path including at feast a digital-to-analog converter that performs Sigma-Delta modulation.

5. A computer system as recited in claim 4,

wherein the receive path further includes a decimation filter, and

wherein the transmit path further includes an interpolation filter.

6. A computer system as recited in claim 3, wherein said codec comprises:

a transmit path, said transmit path includes,

an outgoing buffer that temporarily stores outgoing digital signals being received;

an interpolation filter that performs interpolation processing on the outgoing digital signals to produce processed digital signals;

a digital-to-analog converter that converts the processed digital signals to analog signals for transmission;

a low pass filter that low pass filters the analog signals for transmission; and

a receive path, said receive path includes,

an amplifier that amplifies analog signals being received;

an analog-to-digital converter that converts the amplified analog signals to digital signals;

a decimation filter that performs decimation processing on the digital signals to produce processed digital signals; and

an outgoing buffer that temporarily stores the processed digital signals.

7. A USB codec modem peripheral device that uses a host processor for modulation and demodulation processing, said USB codec modem peripheral device comprises:

a USB bus interface coupled to the host processor via a USB bus;

a codec operatively connected to said USB bus interface, said codec performs analog-to-digital conversions on incoming signals and digital-to-analog conversions on outgoing signals; and

a hybrid circuit operatively connected to said codec, said hybrid circuit couples the outgoing signals to a transmission medium and couples incoming signals to the transmission medium;

wherein said USB codec modem peripheral device does not include modem circuitry that performs modulation and demodulation operations and the host computer implements modulation and demodulation operations using the host processor of the host computer;

wherein a host computer includes the host processor and controls the USB bus using a serial bus host controller, and

wherein said USB bus interface comprises;

a USB peripheral bus interface that couples to the USB bus and interacts with a serial bus host controller to transmit data packets between said computer and said codec modem;

a transmit buffer that temporarily stores data to be transmitted by said codec modem over the transmission medium;

a receiver buffer that temporarily stores data received by said codec modem over the transmission medium;

a buffer management and control unit, said buffer management and control unit operates to manages said transmit buffer and said receive buffer and to control overall operation of said USB bus interface; and

a remote wakeup unit, said remote wakeup unit monitors external signals and notifies said buffer management and control logic unit at least when a wakeup of the USB bus and/or said modem codec is needed.

8. A computer system as recited in claim 7, wherein the notification provided by said remote wakeup unit is further used to wakeup said computer.

9. A computer system as recited in claim 7, wherein said USB bus interface further comprises:

a power manager, said power manager manages the power consumption of said modem codec based on a mode of the USB bus.