QSPI tests: make more robust by immediately detecting deasserted CS line

software/tests/gateware/test_qspi.py

@@ -1,6 +1,6 @@
 import unittest
 from amaranth import *
-from amaranth.sim import Simulator
+from amaranth.sim import Simulator, BrokenTrigger
 from amaranth.lib import io
 
 from glasgow.gateware.ports import PortGroup
@@ -26,8 +26,11 @@ class CSDeasserted(Exception):
  pass
 
  async def watch_cs(cs_o, triggers):
- *values, cs_o = await triggers.sample(cs_o)
- if cs_o == 1:
+ try:
+ *values, posedge_cs_o, cs_o = await triggers.posedge(cs_o).sample(cs_o)
+ except BrokenTrigger: # Workaround for amaranth bug: https://github.com/amaranth-lang/amaranth/issues/1508
+ raise CSDeasserted # both our original trigger and posedge of cs happened at the same time. We choose to prioritize CS being deasserted.
+ if posedge_cs_o or cs_o == 1:
  raise CSDeasserted
  return values