Communications device, method for communications control, and printer comprising this communications device

• US 20080010389A1
• Filed: 07/03/2007
• Published: 01/10/2008
• Est. Priority Date: 07/06/2006
• Status: Active Grant

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Holdings Co., Ltd. (Citizen Electronics Company Limited)
• Inventors: Iwata, Masaji
• Granted Patent: US 7,761,620 B2
• Time in Patent Office: Days
• US Class Current: 710/029
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G06F 2213/0042 Universal serial bus [USB]

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.

Claims

1. A communications device comprising:

a communications buffer connected by a USB bus to a host device, and configuring an endpoint of a USB connection; and

a control unit, wherein

the communications buffer comprises a receive buffer for storing receive data, and

the control unit varies a receive buffer size of the receive buffer in which the communications buffer stores the receive data, based on an instruction sent through USB virtual serial communication from the host device side.

2. The communications device according to claim 1, wherein

the instruction is an instruction for designating whether flow control is active or inactive in a serial interface protocol between the host device and a communications device,

the control unit varies the receive buffer size of the receive buffer provided in the communications buffer based on specifying active or inactive of the flow control in the instruction, and

control is performed such that the receive buffer size of the receive buffer provided in the communications buffer is increased based on the specification that the flow control is inactive, and the receive buffer size of the receive buffer provided in the communications buffer is decreased based on the specification that the flow control is active.

3. The communications device according to claim 2, wherein

the communications buffer is provided with a memory region including a plurality of regions that can be separated and linked freely in software,

the control unit controls a portion of the plurality of regions as the receive buffer and controls the rest of the regions as free regions,

the receive buffer size is increased by linking the receive buffer and a free region, in software and by incorporating the free region into the receive buffer, based on the specifying that the flow control is inactive, and

the receive buffer size is decreased by separating, in software, the receive buffer from the free region based on the specification that the flow control is active.

4. The communications device according to claim 1, comprising:

an analyzing unit for analyzing stored data that is stored in the receive buffer; and

a forwarding unit for forwarding commands that have been analyzed by the analyzing unit, wherein

the forwarding unit forwards, to an external device that is connected through a USB interface, the commands obtained through the analysis of the analyzing unit.

5. The communications device according to claim 2, comprising:

an analyzing unit for analyzing stored data that is stored in the receive buffer; and

a forwarding unit for forwarding commands that have been analyzed by the analyzing unit, wherein

the forwarding unit forwards, to an external device that is connected through a USB interface, the commands obtained through the analysis of the analyzing unit.

6. The communications device according to claim 3, comprising:

an analyzing unit for analyzing stored data that is stored in the receive buffer; and

a forwarding unit for forwarding commands that have been analyzed by the analyzing unit, wherein

the forwarding unit forwards, to an external device that is connected through a USB interface, the commands obtained through the analysis of the analyzing unit.

7. The communications device according to claim 1, comprising:

an analyzing unit for analyzing stored data that is stored in the receive buffer; and

a printer buffer, wherein

the printer buffer stores printing data obtained through the analysis by the analyzing unit.

8. The communications device according to claim 2, comprising:

an analyzing unit for analyzing stored data that is stored in the receive buffer; and

a printer buffer, wherein

the printer buffer stores printing data obtained through the analysis by the analyzing unit.

9. The communications device according to claim 3, comprising:

an analyzing unit for analyzing stored data that is stored in the receive buffer; and

a printer buffer, wherein

the printer buffer stores printing data obtained through the analysis by the analyzing unit.

17. A printer comprising the printer communications device according to claim 1, comprising:

an analyzing unit for analyzing stored data stored in a receive buffer;

a printer mechanism for performing printing; and

a printer buffer for storing print data used for printing in the printer mechanism, wherein

the control unit stores in a printer buffer the print data obtained from the analyzing unit; and

the printer mechanism is driven and controlled by commands obtained by the analyzing unit.

10. A method of communications control in communications through USB virtual serial communication between a host device and a communications device that are connected with USB connection, wherein

a receive buffer size of a receive buffer that stores receive data of a communications buffer provided in the communications device changes, based on instructions sent from the host device side through USB virtual serial communication.

11. The method of communications control according to claim 10, wherein

the instruction is a specification designating whether flow control is active or inactive in a serial interface protocol between the host device and the communications device, and wherein,

in the communications device, an instruction that the flow control is inactive is received from the host device to increase the receive buffer size, and an instruction that the flow control is active is received from the host device to decrease the receive buffer size.

12. The method of communications control according to claim 10, wherein

the communications buffer comprises a memory region including a plurality of regions that can be separated or linked in software,

a portion of the plurality of regions is a receive buffer, and the rest of the regions are free regions,

the size of the receive buffer is increased by linking the receive buffer and a free region in software and by incorporating the free region into the receive buffer, and

the receive buffer is separated from the free region in software to decrease the size of the receive buffer.

13. The method of communications control according to claim 11, wherein

the communications buffer comprises a memory region including a plurality of regions that can be separated or linked in software,

a portion of the plurality of regions is a receive buffer, and the rest of the regions are free regions,

the size of the receive buffer is increased by linking the receive buffer and a free region in software and by incorporating the free region into the receive buffer, and

the receive buffer is separated from the free region in software to decrease the size of the receive buffer

14. The method of communications control according to claim 13, wherein proportions of the plurality of regions are set freely by an instruction from the host device side.

15. The method for communications control according to claim 11, wherein

the free region includes a plurality of regions, and

any given number of regions selected from the plurality of regions can be linked to the receive buffer to selectively increase the size of the receive buffer.

16. The method for communications control according to claim 12, wherein

the free region includes a plurality of regions, and

any given number of regions selected from the plurality of regions can be linked to the receive buffer to selectively increase the size of the receive buffer.