US 8,015,465 B2Granted

Scan control method and device

AssigneeFujitsu Limited

InventorsYoshikazu Iwami, Takayuki Kinoshita, Hidekazu Osano

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Abstract

A scan control method of a circuit device including setting information indicating scan mode in a register is provided. The scan control method includes cutting an output of scan-out data to a test access port controller and an input of scan-in data from a data register based on information set in the register, and controlling a connection between a scan register and a data register. Each data/scan register includes data registers for the same number of chains to be scanned at the same time. Data set in one data register may be kept in all the data registers in parallel and scanned in all the scan chains in a scan-in process in the broadcast mode. The data set in the data register may be kept in the data register corresponding to the scan register and scanned in the corresponding scan chain, in a scan-in process in the parallel mode.

Claims8

Dependent claims

A scan control method of a circuit device, connected with a bus, having a test access port controller, the method comprising:

setting information indicating one scan mode of a broadcast mode, a parallel mode, and a normal mode in a register unit;
and
cutting an output of scan out data to the test access port controller and an input of scan in data from a data register unit based on the information set in the register unit and controlling a connection between a scan register unit and the data register unit,
wherein each of the data register unit and the scan register unit includes data registers for the same number of chains to be scanned at the same time,
data set in one data register of the data register unit is kept in all the data registers of the scan register unit in parallel and scanned in all the scan chains in a scan in of the broadcast mode at a time of controlling the scan register unit and the data register unit, and
the data set in the data register of the data register unit is kept in the data register corresponding to the scan register unit and scanned in the corresponding scan chain, in a scan in of the parallel mode.

3 more elements

A device having a test access port controller, connected with a bus, comprising:

a register unit where information indicating one scan mode of a broadcast mode, a parallel mode, and a normal mode, is set;
a data register unit where a scan in data is set;
a scan register unit;
and
a scan chain rearrangement unit which cuts an output of scan out data to the test access port controller and an input of scan in data from the data register unit and controls a connection between the scan register unit and the data register unit, based on the information set in the register unit,
wherein each of the data register unit and the scan register unit includes the data registers for the same number of chains to be scanned at the same time, and
the scan chain rearrangement unit controls the connection between the scan register unit and the data register unit so that the data set in one data register of the data register unit is kept in all the data registers of the scan register unit in parallel and scanned in all the scan chains in the broadcast mode, and that the data set in the data register of the data register unit is kept in the corresponding data register of the scan register unit and scanned in the corresponding scan in chain in a scan in of the parallel mode.

4 more elements

Dependencies are inferred from the claim text.