Communications device, and communications method for enabling reception of real-time execution commands when a receive buffer is full
First Claim
Patent Images
1. A communications system comprising:
- a host device;
a communications buffer connected by a universal serial bus (USB) interface to the host device, and configuring an endpoint of a USB connection, wherein the communications buffer comprises a receive buffer for receiving and storing data sent from the host device;
a control unit;
an analyzing unit analyzing stored data that is stored in the receive buffer; and
a forwarding unit forwarding commands that have been analyzed by the analyzing unit to an external device through the USB interface;
wherein the control unit varies a size of the receive buffer in which the communications buffer stores the data sent from the host device, based on an instruction specifying whether flow control is active or inactive on data communicating between the host device and the receive buffer sent through a USB virtual serial communication driver from the host device, and a control is performed such that the receive buffer size is increased if the flow control is inactive and the receive buffer size is decreased if flow control is active.
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Abstract
A communications buffer and control unit that configure a USB connection endpoint are provided connected by a USB bus to a host device. The control unit changes the receive buffer size of a receive buffer where the communications buffer stores receive data, based on an instruction that is sent from the host device side through USB virtual serial communication, to enable the reception of real-time execution commands by the communications device. This enables the reception of real-time execution commands when the receive buffer on the communications device side is in a buffer-full state in data communications between a host device and a communications device.
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Citations
10 Claims
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1. A communications system comprising:
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a host device; a communications buffer connected by a universal serial bus (USB) interface to the host device, and configuring an endpoint of a USB connection, wherein the communications buffer comprises a receive buffer for receiving and storing data sent from the host device; a control unit; an analyzing unit analyzing stored data that is stored in the receive buffer; and a forwarding unit forwarding commands that have been analyzed by the analyzing unit to an external device through the USB interface; wherein the control unit varies a size of the receive buffer in which the communications buffer stores the data sent from the host device, based on an instruction specifying whether flow control is active or inactive on data communicating between the host device and the receive buffer sent through a USB virtual serial communication driver from the host device, and a control is performed such that the receive buffer size is increased if the flow control is inactive and the receive buffer size is decreased if flow control is active. - View Dependent Claims (3, 4, 5, 10)
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2. A method of communications control in communications through USB virtual serial communication between a host device and a communications device that are connected with a USB connection, the communications device including a communications buffer having a receive buffer for receiving and storing data sent from the host device, comprising:
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receiving an instruction specifying whether flow control is active or inactive on data communicating between the host device and the receive buffer sent through a USB virtual serial communication driver; analyzing, in an analyzing unit, stored data in the receive buffer; forwarding, in a forwarding unit, analyzed commands to an external device through the USB interface; and varying a size of the receive buffer based on the instruction for controlling the flow of data between the host device and the receive buffer sent from the host device through USB virtual serial communication, and a control is performed such that the receive buffer size is increased if the flow control is inactive and the receive buffer size is decreased if the flow control is active. - View Dependent Claims (6, 7, 8, 9)
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Specification