31
AT94KAL Series FPSLIC
Rev. 1138G–FPSLI–11/03
SCR6
0 = OTS Disabled
1 = OTS Enabled
Setting SCR6 makes the OTS (output tri-state) pin an input which controls the
global tri-state control for all user I/O. This junction allows the user at any time to
tristate all user I/O and isolate the chip.
SCR7 - SCR12
Reserved
SCR13
0 = CCLK Normal Operation
1 = CCLK Continues After Configuration.
Setting bit SCR13 allows the CCLK pin to continue to run after configuration
download is completed. This bit is valid for Master mode, mode 0 only. The CCLK
is not available internally on the device. If it is required in the design, it must be
connected to another device I/O.
SCR14 - SCR15
Reserved
SCR16 - SCR23
0 = GCK 0:7 Always Enabled
1 = GCK 0:7 Disabled During Internal and External Configuration Download.
Setting SCR16:SCR23 allows the user to disable the input buffers driving the
global clocks. The clock buffers are enabled and disabled synchronously with the
rising edge of the respective GCK signal, and stop in a High “1” state. Setting one
of these bits disables the appropriate GCK input buffer only and has no effect on
the connection from the input buffer to the FPGA array.
SCR24 - SCR25
0 = FCK 0:1 Always Enabled
1 = FCK 0:1 Disabled During Internal and External Configuration Download.
Setting SCR24:SCR25 allows the user to disable the input buffers driving the fast
clocks. The clock buffers are enabled and disabled synchronously with the rising
edge of the respective FCK signal, and stop in a High “1” state. Setting one of
these bits disables the appropriate FCK input buffer only and has no effect on the
connection from the input buffer to the FPGA array.
SCR26
0 = Disable On-chip Debugger
1 = Enable On-chip Debugger.
JTAG Enable, SCR27, must also be set (one) and the configuration memory
lockout, SCR4, must be clear (zero) for the user to have access to internal scan
chains.
SCR27
0 = Disable TAP at user FPGA I/O Ports
1 = Enable TAP at user FPGA I/O Ports.
Device ID scan chain and AVR I/O boundary scan chain are available. The user
must set (one) the On-chip Debug Enable, SCR26, and must keep the
configuration memory lockout, SCR4, clear (zero) for the user to have access to
internal scan chains.
SCR28 - SCR29
Reserved
SCR30
0 = Global Set/Reset Normal
1 = Global Set/Reset Active (Low) During Internal and External Configuration
Download.
SCR30 allows the Global set/reset to hold the core DFFs in reset during any
configuration download. The Global set/reset net is released at the end of
configuration download on the rising edge of CON, if set.
SCR31
0 = Disable I/O Tri-state
1 = I/O Tri-state During (Internal and External) Configuration Download.
SCR31 forces all user defined I/O pins to go tri-state during configuration
download. Tri-state is released at the end of configuration download on the rising
edge of CON, if set.
Table 11.
FPSLIC System Control Register
Bit
Description