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26 www.xilinx.com SPI-4.2 Lite v4.3 User Guide
UG181 June 27, 2008
Chapter 2: Core Architecture
R
Sink Static Configuration Interface
These signals are inputs to the core that are statically driven by setting them to a constant
value in the top-level wrapper file. The SPI-4.2 Lite release includes a wrapper file that has
the static configuration signals connected to the values selected in the CORE Generator
GUI. Customization of these signals can be done using the GUI.
Two of the Sink Static Configuration signals can be changed in circuit. There are static
registers for
SnkCalendar_M and SnkCalendar_Len that are synchronous to SnkStatClk.
To change these parameters while the core is operational,
SnkEn must first be deasserted.
If you sets the configuration signal to an illegal number, the core is automatically set to the
minimum value. Table 2-6 defines the Sink Static Configuration signals.
SnkStatAddr[3:0] Input SnkStatClk Sink Status Address bus: The Sink Status Address determines the
group of 16-channel status that SnkStat will be updating.
Bank 0: SnkStatAddr=0, channels 15 to 0
Bank 1: SnkStatAddr=1, channels 31 to 16
Bank 2: SnkStatAddr=2, channels 47 to 32
. . .
Bank 15: SnkStatAddr=15, channels 255 to 239
SnkStatWr_n Input SnkStatClk Sink Status Write: The Sink Status Write (active low) qualifies the
SnkStatMask signal. When SnkStatWr_n is asserted (active low),
status for the different channels is updated. When SnkStatWr_n is
deasserted (active high), SnkStat input is ignored.
SnkStatMask[15:0] Input SnkStatClk Sink Status Mask Bus: The Sink Status Mask determines if the 2-bit
status among the corresponding group of 16 channels of status on
SnkStat (being addressed by SnkStatAddr) will be updated when
SnkStatWr_n is asserted (active low):
SnkStatMask[x] = 1, status for channel (x+(SnkStatAddr*16)) will be
updated.
SnkStatMask[y] = 0, status for channel (y+(SnkStatAddr*16)) will not
be updated.
For example, if SnkStatMask[15] = 1 and SnkStatAddr = 1, then
SnkStat[31:30] = 00 will overwrite the current status on channel 31. If
SnkStatMask is all zeros, none of the sixteen 2-bit status values will
be updated. If SnkStatMask is all ones, all sixteen of the 2-bit status
values will be updated.
Table 2-5: Sink Status FIFO Signals (Continued)
Name Direction
Clock
Domain
Description