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US 10,209,304 B2Granted
Test compression in a JTAG daisy-chain environment
AssigneeTexas Instruments Incorporated
InventorLee D. Whetsel
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Abstract
The disclosure describes novel methods and apparatuses for controlling a device's TCA circuit when the device exists in a JTAG daisy-chain arrangement with other devices. The methods and apparatuses allow the TCA test pattern set used during device manufacturing to be reused when the device is placed in a JTAG daisy-chain arrangement with other devices, such as in a customers system using the device. Additional embodiments are also provided and described in the disclosure.
Claims7
An electrical system comprising:
- (a) a system test data in input, a system test clock input, a system test mode select input, and a system test data out output;
- (b) a first device having:
- (i) a first test access port including a first test data in input coupled to the system test data in input, a first test clock input coupled to the system test clock input, a first test mode select input coupled to the system test mode select input, a first test data out output, a first scan data input, a first scan clock output, and a first scan enable output;
- and
- (ii) a first test compression architecture circuit having a first compressed data input coupled to the system test data in input lead, a first compressed data output coupled to the first scan data input, a first scan clock input coupled to the first scan clock output, and a first scan enable input coupled to the first scan enable output;
- (c) a second device having:
- (i) a second test access port including a second test data in input coupled to the first test data out output, a second test clock input coupled to the system test clock input, a second test mode select input coupled to the system test mode select input, a second test data out output coupled to the system test data out output, a second scan data input, a second scan clock output, and a second scan enable output;
- and
- (ii) a second test compression architecture circuit having a second compressed data input coupled to the first test data out output, a second compressed data output coupled to the second scan data input, a second scan clock input coupled to the second scan clock output, and a second scan enable input coupled to the second scan enable output.
6 more elements
Dependencies are inferred from the claim text.