AD9161/AD9162 Data Sheet
Rev. D | Page 62 of 144
JESD204x Mode Required Samples from JESD204x Tx Samples Assignment
4× Four-Lane (L = 4, M = 2, F = 1, S = 1) Send two samples: M0S0, M1S0, repeat SP0: M0S0, SP4: M0S0, SP8: M0S0, SP12: M0S0
6× Four-Lane (L = 4, M = 2, F = 1, S = 1) SP1: M1S0, SP5: M1S0, SP9: M1S0, SP13: M1S0
8× Four-Lane (L = 4, M = 2, F = 1, S = 1) SP2: M0S0, SP6: M0S0, SP10: M0S0, SP14: M0S0
12× Four-Lane (L = 4, M = 2, F = 1, S = 1) SP3: M1S0, SP7: M1S0, SP11: M1S0, SP15: M1S0
16× Four-Lane (L = 4, M = 2, F = 1, S = 1)
24× Four-Lane (L = 4, M = 2, F = 1, S = 1)
8× Two-Lane (L = 2, M = 2, F = 2, S = 1)
12× Two-Lane (L = 2, M = 2, F = 2, S = 1)
16× Two-Lane (L = 2, M = 2, F = 2, S = 1)
24× Two-Lane (L = 2, M = 2, F = 2, S = 1)
16× One-Lane (L = 1, M = 2, F = 4, S = 1)
24× One-Lane (L = 1, M = 2, F = 4, S = 1)
1 Mx is the converter number and Sy is the sample number. For example, M0S0 means Converter 0, Sample 0. SPx is the sample pattern word number. For example, SP0
means Sample Pattern Word 0.
Repeated CGS and ILAS Test
As per Section 5.3.3.8.2 of the JESD204B specification, the
AD9161/AD9162 can check that a constant stream of /K28.5/
characters is being received, or that CGS followed by a constant
stream of ILAS is being received.
To run a repeated CGS test, send a constant stream of /K28.5/
characters to the AD9161/AD9162 SERDES inputs. Next, set up
the device and enable the links. Ensure that the /K28.5/ characters
are being received by verifying that SYNCOUT± is deasserted
and that CGS has passed for all enabled link lanes by reading
Register 0x470.
To run the CGS followed by a repeated ILAS sequence test,
follow the procedure to set up the links, but before performing
the last write (enabling the links), enable the ILAS test mode by
writing a 1 to Register 0x477, Bit 7. Then, enable the links. When
the device recognizes four CGS characters on each lane, it
deasserts the SYNCOUT±. At this point, the transmitter starts
sending a repeated ILAS sequence.
Read Register 0x473 to verify that initial lane synchronization has
passed for all enabled link lanes.
JESD204B ERROR MONITORING
Disparity, Not in Table, and Unexpected Control (K)
Character Errors
As per Section 7.6 of the JESD204B specification, the AD9161/
AD9162 can detect disparity errors, not in table (NIT) errors,
and unexpected control character errors, and can optionally
issue a sync request and reinitialize the link when errors occur.
Note that the disparity error counter counts all characters with
invalid disparity, regardless of whether they are in the 8-bit/10-bit
decoding table. This is a minor deviation from the JESD204B
specification, which only counts disparity errors when they are
in the 8-bit/10-bit decoding table.
Several other interpretations of the JESD204B specification are
noted in this section. When three NIT errors are injected to one
lane and QUAL_RDERR (Register 0x476, Bit 4) = 1, the readback
values of the bad disparity error (BDE) count register is 1.
Reporting of disparity errors that occur at the same character
position of an NIT error is disabled. No such disabling is per-
formed for the disparity errors in the characters after an NIT
error. Therefore, it is expected behavior that an NIT error may
result in a BDE error.
A resync is triggered when four NIT errors are injected with
Register 0x476, Bit 4 = 1. When this bit is set, the error counter
does not distinguish between a concurrent invalid symbol with
the wrong running disparity but is in the 8-bit/10-bit decoding
table, and a NIT error. Thus, a resync can be triggered when
four NIT errors are injected because they are not distinguished
from disparity errors.
Checking Error Counts
The error count can be checked for disparity errors, NIT errors,
and unexpected control character errors. The error counts are
on a per lane and per error type basis. Each error type and lane
has a register dedicated to it. To check the error count, the
following steps must be performed:
1. Choose and enable which errors to monitor by selecting
them in Register 0x480, Bits[5:3] to Register 0x487,
Bits[5:3]. Unexpected K (UEK) character, BDE, and NIT
error monitoring can be selected for each lane by writing a
1 to the appropriate bit, as described in the register map.
These bits are enabled by default.
2. The corresponding error counter reset bits are in
Register 0x480, Bits[2:0] to Register 0x487, Bits[2:0].
Write a 0 to the corresponding bit to reset that error
counter.
3. Registers 0x488, Bits[2:0] to Register 0x48F, Bits[2:0] have
the terminal count hold indicator for each error counter. If
this flag is enabled, when the terminal error count of 0xFF
is reached, the counter ceases counting and holds that
value until reset. Otherwise, it wraps to 0x00 and continues
counting. Select the desired behavior and program the
corresponding register bits per lane.