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SPI-4.2 Lite v4.3 User Guide www.xilinx.com 27
UG181 June 27, 2008
Sink Core Interfaces
R
Table 2-6: Sink Static Configuration Signals
Name Direction Range Description
NumDip4Errors[3:0] Static
Input
1-15
Value of 0 is set to 1
Number of DIP-4 Errors: The Sink Interface will go
out-of-frame (assert SnkOof) and stop accepting data
from the SPI-4.2 bus after receiving NumDip4Errors
consecutive DIP-4 errors.
NumTrainSequences[3:0] Static
Input
1-15
Value of 0 is set to 1
Number of Complete Training Sequences: A
complete training pattern consists of 10 training
control words and 10 training data words. The Sink
interface requires NumTrainSequences consecutive
training patterns before going in frame (deasserting
SnkOof) and accepting data from the SPI-4.2 bus.
SnkCalendar_M[7:0] Input 0-255
(effective range 1-256)
Sink Calendar Period: The SnkCalendar_M parameter
sets the number of repetitions of the calendar sequence
before the DIP-2 parity and framing words are
inserted.
The core implements this parameter as a static register
synchronous to SnkStatClk, and it can be updated in
circuit by first deasserting SnkEn.
Note that the Sink Calendar Period equals
SnkCalendar_M + 1. For example, if
SnkCalendar_M=22, the Sink Calendar Period will be
equal to 23.
SnkCalendar_Len[8:0] Input 0-511
(effective range 1-512)
Sink Calendar Length: The SnkCalendar_Len
parameter sets the length of the calendar sequence.
The core implements this parameter as a static register
synchronous to SnkStatClk, and it can be updated in
circuit by first deasserting SnkEn.
Note that the Sink Calendar Length equals
SnkCalendar_Len + 1. For example, if
SnkCalendar_Len=15, the Sink Calendar Length will
be equal to 16.
SnkAFThresAssert[8:0] Static
Input
1–508
Values less than1 are
set to 1.
Values greater than
508 are set to 508.
Sink Almost Full Threshold Assert: The
SnkAFThresAssert parameter defines the minimum
number of empty FIFO locations that exist when
SnkAlmostFull_n is asserted. Note that the assert
threshold must be less than or equal to the negate
threshold (SnkAFThresNegate).
When SnkAlmostFull_n is asserted, the core initiates
the flow control mechanism selected by the parameter
FifoAFMode. The FifoAFMode defines when the
interface stops sending valid FIFO status levels and
begins sending flow control information on RStat. This
indicates to the transmitting device that the core is
almost full and additional data cannot be sent.