Unsupported Ports in Arria 10 Native Fixed Point DSP IP Core for m18x18_full and m27x27 Operation Modes

Description

When you configure the Arria 10 Native Fixed Point DSP IP to m27x27 or m18x18_full operation mode, the following ports are not supported but visible to users:

• Operation mode: m18x18_full
• Unsupported ports: ACCUMULATE, LOADCONST, SUB and NEGATE ports

• Operation mode: m27x27
• Unsupported ports: SUB port

If you assert or deassert the ACCUMULATE, LOADCONST, SUB, and NEGATE ports in m18x18_full operation mode, the DSP core does not perform any operations enabled by these ports. If you assert or deassert the SUB port when using the Arria 10 Native Fixed Point DSP IP in m27x27 operation mode, the DSP core does not perform any arithmetic operation (addition or subtraction).

Resolution

Leave the ACCUMULATE, LOADCONST, SUB, and NEGATE ports unconnected when using the Arria 10 Native Fixed Point DSP IP in m27x27 and m18x18_full operation modes. This issue will be fixed in a future version of the Quartus II software.