JPH0448341A - Scan path circuit control system - Google Patents

Abstract

PURPOSE:To shorten the scan processing time by providing a control circuit which checks a selector circuit and a scan register and outputs a scan mode signal to set an optional scan path circuit in a scan operable state. CONSTITUTION:A prescribed state is set to a scan register 124, and a scan path constitution control circuit 121 judges the contents of the register 124 and outputs the selection signals 113-115. Thus a selector 103 connects the output of a scan path 108 to the input of a scan path 107. A selector 104 does not connect the input of the path 108. A selector 105 connects the output of the path 107 to the input of a scan path 109 respectively. When another state is set to the register 124, the circuit 121 outputs a selection signal 116. Then a selector 110 connects the output of the path 109 to a scan path collector. As a result, a single scan processing operation suffices and therefore the scan processing time is extremely shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scan path circuit control method, and particularly to a scan path circuit control method when performing a scanning operation on an arbitrary scan path from a group of scan paths.

[Conventional technology]

Conventionally, this type of scan path circuit control method, as shown in FIG. 3, scans scan paths 302 to 305 consisting of a plurality of scan paths and arbitrarily scans one scan path from among the scan paths 302 to 305. A register 306 and a select signal 307 that analyzes the register 306 and sets one specified scan path.
, 312, and at the same time outputs mode signals 308 to 311 for setting the scan path designated by the register 306 to a state in which scan operation is possible.
, a selector circuit 301 that connects only one scan path specified in response to a select signal 307 so as to enable data input;
It was composed of a selector circuit 314 that connects only the scan path of 1 to enable data output.

[Problem to be solved by the invention]

In the conventional scan path circuit control method described above, one scan path is stored in the register where the scan operation instruction is set.
If this is specified, only one specified scan path will be processed, so if you need data from multiple scan paths, repeat the scan operation for the number of scan paths that require scanning. Therefore, the disadvantage is that the more scan paths are required, the longer the scan processing time becomes.

[Means to solve the problem]

The scan path circuit control method of the present invention includes a scan path and a scan path circuit control method in which registers are serially connected. A scan register that can specify a scan path, a scan path configuration control circuit that examines the scan register and issues a configuration signal that splices specified arbitrary scan paths into one scan path, and an input for a group of scan paths. a selector circuit that connects the side and output side into one scan path according to configuration signals; and a scan mode control circuit that checks the scan register and issues a scan mode signal that makes any scan path circuit ready for scan operation. have.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In this embodiment, the configuration and operation when there are four scan paths are as shown in FIG.
The case of scanning 07 and 109 will be explained.

101 is input from the scan path collection device, 103-1
05 is the scan path input selector 106 to 10
9 is the scan path, 110 is the output selector 111
113 to 115 are select signals, 117 to 120 are mode signals, 121 is a scan path configuration control circuit, 122 is a scan path mode control circuit, and 124 is a scan register that specifies the scan path state. Then, Table 1 is written in the scan register 124.
When state C is set, the scan path configuration control circuit 121 determines the contents of the scan register and outputs select signals 113 to 115, and the selector 103 inputs the output of the scan path 106 to the input of the scan path 107. connection, selector 104 does not connect input of scan path 108, selector 105 connects scan path 107
The output of is connected to the input of scan path 109.

Further, when the state of C is set according to Table 2, the scan path configuration control circuit outputs the select signal 116, and the selector 110 connects the pressure of the scan path 109 to the scan path sampling device. On the other hand, in the scan path mode, according to Table 3, when the scan path mode control circuit 122 determines that the contents of the scan register are in the state C, it outputs mode signals 117 to 120 to control the scan path 106.
, 107° 109 are activated.

In other cases, the configuration of the scan path is controlled in accordance with Table 1.2.3 in the same manner as described above.

The configuration and operation when the number of scan paths is n can be easily realized by extending this embodiment.

Table 1 Selector control table on the input side when there are 4 scan paths 2 Selector control table on the output side when there are 4 scan paths 3 Scan mode when there are 4 scan paths Control [Effects of the Invention] As explained above, the present invention makes it possible to specify any scan path (one scan path or multiple scan paths) required for the scan register. Using the scan path configuration control circuit and selector circuit, connect any scan paths that have been created into a single scan path, and at the same time set any scan path mode requested by the mode control circuit to a state in which scan operation is possible. By doing so, it becomes possible to process the scan processing performed for the number of requested scan canvases in one scan processing, which has the effect of significantly shortening the scan processing time.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
FIG. 3 is a block diagram showing a conventional example of the connection diagram of scan canvases when scan canvases 1, 2, and 4 are requested in the embodiment shown in the figure. 101...Path from the scan path data collection device, 103-105...Selector on the scan path input side 106-109...Scan path, 110... Output side selector 111・
...Path to scan path data collection device, 11
3 to 115...Select signal issued from the scan canvas configuration control circuit to the selector on the input side, 1i
6...Select signal issued from the scan canvas configuration control circuit to the selector on the output side, 117 to 12
0...Scan mode signal, 121...
・Su ++ path m formation control circuit L 122...Group・Scan path mode control circuit, 124...Scan path register 301.314...Selector 302-305...Scan Bus, 306・
・Mountain register, 307° 312...Select signal, 308-311...Mode signal, 31
3... Control circuit. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] In a scan path and scan path circuit control system in which registers are serially connected, a scan path group consisting of a plurality of scan paths, and from the scan path group,
a scan register that specifies the scan operation of one or more scan paths; and a scan path configuration control circuit that examines the scan register and outputs a configuration signal that splices specified arbitrary scan paths into one scan path. a selector circuit that connects the input side and output side of a group of scan paths into one scan path according to the configuration signal; and a scan mode that checks the scan register and makes any scan path circuit ready for scanning operation. A scan path circuit control method comprising: a scan mode control circuit that outputs a signal.