如何在Vivado仿真器中强制自定义数据类型值？代码是否可综合？

Hey there! Let's break down your two questions clearly and practically:

1. Correct add_force Syntax for Custom Record Types #

Vivado's Tcl console doesn't support forcing an entire custom record signal in one go—you need to target each individual field within the record separately. The comma/semicolon errors you're hitting come from trying to treat the composite record like a single scalar signal, which it isn't.

Let's use a typical example of your my_datatype to illustrate:

type my_datatype is record
    data    : std_logic_vector(7 downto 0);
    valid   : std_logic;
    ready   : std_logic;
end record;

Suppose your a_in signal (of type my_datatype) lives in a hierarchy like /testbench/dut/a_in. You'll need separate add_force commands for each field:

# Force the 8-bit data field to hex value 0xAA
add_force /testbench/dut/a_in/data 0xAA

# Force the valid flag to logic high
add_force /testbench/dut/a_in/valid 1

# Force the ready flag to logic low
add_force /testbench/dut/a_in/ready 0

If your signal path includes spaces or special characters, wrap the path in curly braces to avoid parsing issues:

add_force {/testbench top/dut/a_in/data} 0x55

A quick pro tip: Use Vivado's GUI to find the exact hierarchical path of each record field (right-click the signal > Copy Path) to avoid typos.

2. Synthesis Compatibility of VHDL Code with Custom Records #

Great news: Custom VHDL record types are fully synthesizable in Vivado 2013.4, as long as you follow a few simple rules:

• All sub-fields must use synthesizable types: Stick to standard types like std_logic, std_logic_vector, unsigned, signed, or constrained integers. Skip non-synthesizable types like access (pointers) or unconstrained arrays.
• If using the record as a module port, declare the type in a shared package so the synthesizer can resolve it across different modules.
• Never use unconstrained fields: For example, data : std_logic_vector; (no bit width specified) won't synthesize—always define a fixed range like data : std_logic_vector(7 downto 0);.

During synthesis, Vivado will automatically split the record into its individual sub-signals, which will be treated as separate wires in the netlist. This has no impact on your design's functionality—records are just a clean, organized way to group related signals in your code.

内容的提问来源于stack exchange，提问作者Veena