Add assertion for rogue external ack strobes. Clarify recommended external ack tieoff. #57

docs/rdl_features/external.rst

@@ -71,6 +71,9 @@ hwif_in..rd_ack
     Single-cycle strobe indicating a read transfer has completed.
     Qualifies all other read response signals.
 
+    If the transfer is always completed in the same cycle, it is acceptable to
+    tie this signal to ``hwif_out..req && !hwif_out..req_is_wr``.
+
 hwif_in..rd_data
     Read response data.
 
@@ -79,6 +82,9 @@ Write Response
 hwif_in..wr_ack
     Single-cycle strobe indicating a write transfer has completed.
 
+    If the transfer is always completed in the same cycle, it is acceptable to
+    tie this signal to ``hwif_out..req && hwif_out..req_is_wr``.
+
 
 
 External Blocks

src/peakrdl_regblock/module_tmpl.sv

@@ -56,6 +56,10 @@ module {{ds.module_name}} (
         end else begin
             if(external_req & ~external_wr_ack & ~external_rd_ack) external_pending <= '1;
             else if(external_wr_ack | external_rd_ack) external_pending <= '0;
+            assert(external_wr_ack -> (external_pending | external_req))
+                else $error("An external wr_ack strobe was asserted when no external request was active");
+            assert(external_rd_ack -> (external_pending | external_req))
+                else $error("An external rd_ack strobe was asserted when no external request was active");
         end
     end
 {%- endif %}