Diagnosis operation
Posted: 24 Dec 2020, 10:52
To debug memory defects, MBIST should add diagnosis functionality. Without, MBIST only can report memory cells pass or fail result. In START tool, designer can add diagnosis function by setting following parameters
“diagnosis_support”
“diagnosis_data_sharing”
“diagnosis_memory_info”
“diagnosis_time_info”
“diagnosis_faulty_items”
Following picture shows where can set above parameters in START BFL file. In parameter “diagnosis_faulty_items”, designer can decide what memory error information need to be output. These error information include algorithm, operation, element, seq_id, grp_id, address, ram_data, rom_data.
Diagnosis command includes seven items, Algorithm, Sequencer ID, Group ID, Element, Operation, Faulty Address and Faulty Data. The order of these items is fixed. But their width could be different according to customer’s design.
The Waveform below is an example of diagnosis input testing command for IEEE 1149.1 in MBIST architecture. The WIR Reg. is selected to Test_cmd Reg.
The diagnosis result will be sent out over TDO output port. The SRD, MRD and MGO will be shifted out by TDO port. Using following picture as example, where
• SRD
– width = 1, output result is 1’b1 and it means that there is error occurred and diagnosis results need to send out for analysis
• MRD
– width = 1, output result is 1’b0 and it means that the testing is on-going
• MGO
– width = 1, output result is 1’b0 and it means that errors are occurred
Following picture shows diagnosis output data
Where,
• Algorithm
– width = 2, output result is 2’b01 and it means that the first testing algorithm is used
• Sequencer
– width = 1, output result is 1’b1 and it means that the first sequencer is under testing
• Group
– width = 1, output result is 1’b1 and it means that the first group is under testing
• Element
– width = 2, output result is 2’b10 and it means that the second March element is used
• Operation
– width = 2, output result is 2’b10 and it means that the error is occurred at clock cycle 2
• Faulty Address
– width = 4, output result is 4’b1010 and it indicates error address of memory model
• Faulty Data
width = 4, output result is 4’b1110 and it indicates error data of memory model
“diagnosis_support”
“diagnosis_data_sharing”
“diagnosis_memory_info”
“diagnosis_time_info”
“diagnosis_faulty_items”
Following picture shows where can set above parameters in START BFL file. In parameter “diagnosis_faulty_items”, designer can decide what memory error information need to be output. These error information include algorithm, operation, element, seq_id, grp_id, address, ram_data, rom_data.
- Diagnosis_Operation_P1.png (270.14 KiB) Viewed 6175 times
- Diagnosis_Operation_P1.png (270.14 KiB) Viewed 6175 times
Diagnosis command includes seven items, Algorithm, Sequencer ID, Group ID, Element, Operation, Faulty Address and Faulty Data. The order of these items is fixed. But their width could be different according to customer’s design.
- Diagnosis_Operation_P2.png (219.8 KiB) Viewed 6175 times
- Diagnosis_Operation_P2.png (219.8 KiB) Viewed 6175 times
The Waveform below is an example of diagnosis input testing command for IEEE 1149.1 in MBIST architecture. The WIR Reg. is selected to Test_cmd Reg.
- Diagnosis_Operation_P3.png (117.41 KiB) Viewed 6175 times
- Diagnosis_Operation_P3.png (117.41 KiB) Viewed 6175 times
The diagnosis result will be sent out over TDO output port. The SRD, MRD and MGO will be shifted out by TDO port. Using following picture as example, where
• SRD
– width = 1, output result is 1’b1 and it means that there is error occurred and diagnosis results need to send out for analysis
• MRD
– width = 1, output result is 1’b0 and it means that the testing is on-going
• MGO
– width = 1, output result is 1’b0 and it means that errors are occurred
- Diagnosis_Operation_P4.png (99.42 KiB) Viewed 6175 times
- Diagnosis_Operation_P4.png (99.42 KiB) Viewed 6175 times
Following picture shows diagnosis output data
- Diagnosis_Operation_P5.png (104.89 KiB) Viewed 6175 times
- Diagnosis_Operation_P5.png (104.89 KiB) Viewed 6175 times
• Algorithm
– width = 2, output result is 2’b01 and it means that the first testing algorithm is used
• Sequencer
– width = 1, output result is 1’b1 and it means that the first sequencer is under testing
• Group
– width = 1, output result is 1’b1 and it means that the first group is under testing
• Element
– width = 2, output result is 2’b10 and it means that the second March element is used
• Operation
– width = 2, output result is 2’b10 and it means that the error is occurred at clock cycle 2
• Faulty Address
– width = 4, output result is 4’b1010 and it indicates error address of memory model
• Faulty Data
width = 4, output result is 4’b1110 and it indicates error data of memory model