Interface device for host device, interface device for slave device, host device, slave device, communication system and interace voltage switching method

A technology of an accessory device and an interface device, applied in the field of interface circuits, can solve the problems of only switching the voltage of the interface circuit, difficulty in applying interface standards, and difficulty in ensuring the reliability of communication systems, etc.

Active Publication Date: 2010-12-08
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, in the above-mentioned conventional technology, a dedicated terminal for judging the interface voltage is required for each interface voltage, and there is a problem that it is difficult to apply to the existing interface standard whose number of interface lines has been determined.
[0009] In addition, since the master device determines the interface voltage by detecting the judgment key from the slave device, there is no The method of judging whether the switching of the interface voltage of the accessory device has been completed normally, so that there is a problem that it is difficult to ensure the reliability of the communication system
[0010] Furthermore, in the prior art, the premise is that the interface voltage between the master device and the slave device is at the same level as the voltage supplied from the master device to the slave device. The problem of switching only the voltage of the interface circuit stably during operation

Method used

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  • Interface device for host device, interface device for slave device, host device, slave device, communication system and interace voltage switching method
  • Interface device for host device, interface device for slave device, host device, slave device, communication system and interace voltage switching method
  • Interface device for host device, interface device for slave device, host device, slave device, communication system and interace voltage switching method

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Experimental program
Comparison scheme
Effect test

no. 1 Embodiment approach

[0134] figure 1 It is a diagram showing the configuration of the communication system according to the first embodiment of the present invention.

[0135] Such as figure 1 As shown, the communication system according to this embodiment includes a main device 1 and an accessory device 2 . The master device 1 and the slave device 2 are connected by buses 30 to 32 .

[0136] The bus lines 31 and 32 are connected to an output voltage of a regulator described later via pull-up resistors R1 and R2.

[0137] The bus 30 is used for clock sending, the bus 31 is used for command sending and receiving, and the bus 32 is used for data sending and receiving.

[0138] Here, the command is an instruction from the master device 1 to perform register read / write processing, a memory area read / write process, or a process to acquire the status of the slave device 2 to the slave device 2 .

[0139] Although the command / data transmission and reception of the buses 31 and 32 are performed synchr...

Embodiment 1

[0197] use Figure 3A An example (an example) of the communication system of the present embodiment described above will be described.

[0198] In this embodiment (hereinafter referred to as "Embodiment 1"), the first interface voltage is set to "V1" (for example, 3.3 [V]) and the second interface voltage is set to "V1" in the communication system. V2" (for example, 1.8 [V]), the case of switching the interface voltage from "V1" to "V2" will be described.

[0199] In addition, for the convenience of explanation, in Figure 3A The numbers (1) to (9) are assigned in the above, and the operation of the communication system in the first embodiment (processing (1) to (9)) will be described corresponding to the numbers.

[0200] Processing (1):

[0201] The master device 1 issues the command CMD, and then starts a voltage switching sequence (voltage switching process).

[0202] Processing (2):

[0203] The accessory device 2 returns a response to the main device 2 .

[0204] P...

no. 2 Embodiment approach

[0231] Next, use Figure 4 The flow chart of FIG. 2 describes the processing procedure for switching the interface voltage between the master device 1 and the slave device 2 of the communication system according to the second embodiment of the present invention.

[0232] In the communication system according to this embodiment, the input / output terminal 112 of the main device 1 and the input / output terminal 212 of the input / output 2 of the slave device 2 may be open drain outputs. other components and figure 1 The descriptions are the same.

[0233]

[0234] Such as Figure 4 As shown, in the communication system according to the present embodiment, the slave device 2 operates in accordance with commands from the master device 1 . Therefore, when switching the interface voltage, first, the controller 100 of the master device 1 performs a process of issuing an I / F voltage switching command to the slave device 2 (SH401).

[0235] When the controller 200 of the accessory de...

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PUM

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Abstract

In a communication system wherein an operation voltage can be selected from among a plurality of interface voltages, the interface voltage is stably switched while the communication system is operating. A host device (1) and a slave device (2) are configured to switch the interface voltage by stably keeping the signal level of a bus, in the case of switching the interface voltage. Thus, the communication system wherein the interface voltage can be switched by a small number of signal lines is provided.

Description

technical field [0001] The present invention relates to an interface circuit (device) capable of stably and efficiently switching interface voltages during the operation of a main device and an auxiliary device in a communication system capable of selecting an operating voltage from a plurality of interface voltages, and having the interface circuit (device) ), a main device, an auxiliary device, a communication system, and an interface voltage switching method. Background technique [0002] In recent years, attachments such as card-shaped SD cards and memory sticks that have large-capacity nonvolatile storage elements such as flash memory and can perform high-speed data processing have become popular in the market. It is used in main devices that can use accessory devices, that is, personal computers, PDAs (Personal Digital Assistants: Personal Digital Assistants), mobile phones, digital cameras, audio players, car navigation systems, and the like. [0003] In addition, in...

Claims

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Application Information

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IPC IPC(8): G06F1/26
CPCG06F1/26
Inventor 外山昌之吉田贵治坂井敬介
Owner PANASONIC CORP
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