Datasheet

4. Locating Faults
If the test stops with STATUSA.FAIL set, one or more bits failed the test. The test stops at the first
detected error. The position of the failing bit can be found by reading the following registers:
– ADDR: Address of the word containing the failing bit
– DATA: contains data to identify which bit failed, and during which phase of the test it failed. The
DATA register will in this case contains the following bit groups:
Figure 12-6. DATA bits Description When MBIST Operation Returns an Error
Bit
Bit
Bit
Bit
phase
bit_index
31 30
29 28
27
26 25
24
23
22 21
20 19 18
17
16
15
14
13
12 11
10 9 8
7
6 5
4
3
2 1
0
• bit_index: contains the bit number of the failing bit
• phase: indicates which phase of the test failed and the cause of the error, as listed in the following
table.
Table 12-4. MBIST Operation Phases
Phase Test actions
0 Write all bits to zero. This phase cannot fail.
1 Read '0', write '1', increment address
2 Read '1', write '0'
3 Read '0', write '1', decrement address
4 Read '1', write '0', decrement address
5 Read '0', write '1'
6 Read '1', write '0', decrement address
7 Read all zeros. bit_index is not used
Table 12-5. AMOD Bit Descriptions for MBIST
AMOD[1:0] Description
0x0 Exit on Error
0x1 Pause on Error
0x2, 0x3 Reserved
SAM D5x/E5x Family Data Sheet
DSU - Device Service Unit
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 114