Answers Database
M1.4/M1.5: ngdbuild/map:INCDEC-G-0 (cy4_34) is instantiated, got error on INCDEC-G-CI
Record #4182
Product Family: Software
Product Line: FPGA Implementation
Product Part: map
Problem Title:
M1.4/M1.5: ngdbuild/map:INCDEC-G-0 (cy4_34) is instantiated, got error on INCDEC-G-CI
Problem Description:
Keyword: INCDEC, cy4_34, cy4_36, x4kma, 339.
Urgency : Standard
General Description:
Map report the following error:
ERROR:x4kma:339 - The CY4 symbol "$I1" (output signal=COUT0)
has no signal connected to ADD. This pin must be connected
based on carry moded
INCDEC-G-CI
The instantiated carry logic in the design is CY4_34
(INCDEC-G-0) not CY4_36 as reported in the error.
Solution 1:
Another workaround is to add the property CYMODE when
instantiating CY4_34 as follows:
(cell cy4_34 (cellType GENERIC)
(view Netlist_representation (viewType NETLIST)
(interface (port C7 (direction OUTPUT)) (port C6 (direction
OUTPUT))
(port C5 (direction OUTPUT)) (port C4 (direction OUTPUT))
(port C3 (direction OUTPUT)) (port C2 (direction OUTPUT))
(port C1 (direction OUTPUT)) (port C0 (direction OUTPUT))
(property CYMODE (string "INCDEC-G-0")))
(contents)
)
)
and
(instance carryINITcy4 (viewRef Netlist_representation (cellRef
cy4_34))
(property CYMODE (string "INCDEC-G-0")))
Solution 2:
A fix for this problem is included in the 1.5i Service Pack 1. For details
on this Service Pack see http://www.xilinx.com/techdocs/5514.htm
Solution 3:
The error is coming from the NGDBUILD data files that define CY4_34. This mode is defined here to be
INCDEC-G-CI instead of INCDEC-G-0.
CY4_36, which is supposed to be INCDEC-G-CI, is also defined
as INCDEC-G-CI.
A workaround will be to use INC-G-1(cy4_20) or cy4_27(DEC-G-0)
instead.
The above two mode are identical with INCDEC-G-0.
As far as COUT0 and COUT are concerned, INC-G-1, DEC-G-0 and INCDEC-G-0 are all the same. No matter
whether you are incrementing or decrementing, the carry-out/borrow-out from the least-significant bi
t (COUT) is always equal to the bit's current state (G4). If the low bit is zero, that's an active b
orrow-out for decrementing; if the low bit is one, that's an active carry-out for incrementing. So t
he carry-out/borrow-out is independent of the inc/dec mode.
That is, for the least-significant bit:
INC/DEC (F3) CURRENT BIT (G4) CARRY/BORROW-OUT (COUT)
------------ ---------------- --------------------------
1 0 0 (no carry-out)
1 1 1 (active carry-out)
0 0 0 (active borrow-out)
0 1 1 (no borrow-out)
so F3 is a don't-care state here.
End of Record #4182 - Last Modified: 02/02/99 18:52 |
