ORT42G5 Datasheet, PDF (55/119 Pages) Lattice Semiconductor – 0.6 to 3.7 Gbps XAUI and FC FPSCs

Lattice Semiconductor
ORCA ORT42G5 and ORT82G5 Data Sheet
Parallel Loopback at MUX/DEMUX Boundary, Excluding SERDES
This is a low-frequency test mode used to test the MUX/DEMUX logic block. As with the mode described in the pre-
vious section, the loopback path is at the interface between the SERDES blocks and the MUX and DEMUX blocks
and uses the parallel 10-bit buses at these interfaces (see Figure 33). However, the loopback connection is made
such that the output signals from the TX MUX block are used as the input signals to the RX SERDES block. In this
loopback mode the MRWDxx[39:0], TWDxx[31:0], TCOMMAxx[3:0] and TBIT9xx[3:0] signal lines function normally
and the high-speed serial input and output buffers are not used. Use of this mode also requires configuration of the
FPGA logic to connect the MRWDxx[39:0], TWDxx[31:0], TCOMMAxx[3:0] and TBIT9xx[3:0] signal lines to exter-
nal pins. The basic loopback path is shown in Figure 33.
Figure 33. Parallel Loopback at MUX/DEMUX Boundary, Excluding SERDES
Test
Equipment
{
Data
Checking
m
Data
n
Generation
FPGA Logic
MRWDxx[39:0] ⁴⁰
TWDxx[31:0]
TCOMMAxx[3:0]
TBIT9xx[3:0]
Receive
32
4
4
Transmit
Embedded Core
DEMUX
MUX
Parallel
Loopback
Connection
This test mode is enabled by setting the pin PLOOP_TEST_ENN to 0. PASB_TESTCLK must be running in this
mode at 4x frequency of RSYS_CLK[A2, B2] or TSYS_CLK_[AC, AD, BC, BD] for the ORT42G5 and
RSYS_CLK[A1,A2,B1,B2] or TSYS_CLK_[AA, AB... BD] for the ORT82G5.
SERDES Characterization Test Mode (ORT82G5 Only)
The SERDES characterization mode is a test mode that allows for direct control and observation of the transmit
and receive SERDES interfaces at chip ports. With these modes the SERDES logic and I/O can be tested one
channel at a time in either the receive or transmit modes. The SERDES characterization mode is available for only
one quad (quad B) of the ORT82G5.
The characterization test mode is configured by setting bits in the control registers via the system bus. There are
four bits that set up the test mode. The transmit characterization test mode is entered when SCHAR_ENA=1 and
SCHAR_TXSEL=1. Entering this mode will cause chip port inputs to directly control the SERDES low-speed trans-
mit ports of one of the channels as shown in Table 23.
Table 23. SERDES Transmit Characterization Mode
Chip Port
PSCHAR_CKIO0
PSCHAR_LDIO[9:0]
SERDES Input
TBCBx
LDINBx[9:0]
The x in the table will be a single channel in SERDES quad B, selected by the SCHAR_CHAN control bits. The
decoding of SCHAR_CHAN is shown in Table 24.
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