In addition of scala run-time assertion, you can add hardware assertion via the following syntax:
assert(assertion : Bool,message : String = null,severity: AssertNodeSeverity = Error)
Severity levels are :
| Name | Description |
|---|---|
| NOTE | Used to report a informative message |
| WARNING | Used to report a unusual case |
| ERROR | Used to report an situation that should not happen |
| FAILURE | Used to report a fatal situation and close the simulation |
One practical example could be to check that the valid of a handshake protocol never drop when ready is low :
class TopLevel extends Component {
val valid = RegInit(False)
val ready = in Bool
when(ready){
valid := False
}
// some logic
assert(
assertion = !(valid.fall && !ready),
message = "Valid drop when ready was low",
severity = ERROR
)
}