8.3.15 JESD204B Pattern Test
The DAC38RF82 (or DAC38RF89) supports the following test patterns for JESD204B:
- Link layer test pattern by setting field JESD_TEST_SEQ in register JESD_LN_EN (8.5.45) and monitoring the lane alarms (1 = fail, 0 = pass)
- Verify repeating /D.21.5/ high frequency pattern for random jitter (RJ)
- Verify repeating /K.28.5/ mixed frequency pattern for deterministic jitter (DJ)
- Verify repeating initial lane alignment (ILA) sequence
- RPAT, JSPAT or JTSPAT pattern can be verified using errors counter of 8b/10b errors produced over an amount of time to get an estimate of BER.
- Transport layer test pattern: implements a short transport layer pattern check based on F = 1, 2, 4 or 8. The short test pattern has a duration of one frame period and is repeated continuously for the duration of the test. Each sample has a unique value that can be identified with the position of the sample in the user data format. The sample values are such that correct sample values will never be decoded at the receiver if there is a mismatch between the mapping formats being used at the transmitter and receiver devices. This can generally be accomplished by ensuring there are no repeating sub patterns within the stream of samples being transmitted. Refer to the JESD204B standard section 5.1.6 for more details.
The DAC38RF82 (or DAC38RF89) expects the test samples, in a frame, transmitted by an logic device as per Table 38:
Table 38. Short Test Patterns
JESD Mode |
i0 |
q0 |
i1 |
q1 |
82121 |
7CB8, F431 |
6DA9, E520 |
n/a |
n/a |
42111 |
7CB8 |
F431 |
n/a |
n/a |
22210 |
7CB8 |
F431 |
n/a |
n/a |
12410 |
7CB8 |
F431 |
n/a |
n/a |
44210 |
7CB8 |
F431 |
6DA9 |
E520 |
24410 |
7CB8 |
F431 |
6DA9 |
E520 |
41121 |
7CB8, F431 |
n/a |
n/a |
n/a |
81180 |
7C00, B800, F400, 3100, 6D00, A900, E500, 2000 |
n/a |
n/a |
n/a |
24310 |
7CB0 |
F430 |
6DA0 |
E520 |
41380 |
7CB0, F430, 6DA0, E520, F870, E960, DA50, CB40 |
n/a |
n/a |
n/a |
The short test pattern has duration of one frame period and is repeated continuously for the duration of the test. Each sample has a unique value that can be identified with the position of the sample in the user data format. The sample values are such that correct sample values will never be decoded at the receiver if there is a mismatch between the mapping formats being used at the transmitter and receiver devices. This can generally be accomplished by ensuring there are no repeating sub patterns within the stream of samples being transmitted.
Following are the steps required to execute the short test functionality in DAC38RF82 (or DAC38RF89).
- Configure other registers, make sure clocks are up and running.
- Start driving short test patterns
- Clear short test alarm by writing ‘0’ to field ALM_FROM_SHORTTEST in register ALM_SYSREF_PAP (8.5.67). This is a paged register, one for each Multi-DUC.
- Enable short test by writing a ‘1’ to field SHORTTEST_ENA in register MULTIDUC_CFG2 (8.5.14).
- Read the short test alarm from field ALM_FROM_SHORTTEST in register ALM_SYSREF_PAP (8.5.67). This is a paged register, one for each Multi-DUC
If the alarm read from the register is high, the short test has detected an error.