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build.{dsl,plat,res}: allow dir="oe".

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Although a dir="oe" pin is generally equivalent to dir="io" pin with
the i* signal(s) disconnected, they are not equivalent, because some
pins may not be able to support input buffers at all, either because
there are no input buffers, or because the input buffers are consumed
by some other resource.

E.g. this can happen on iCE40 when the input buffer is consumed by
a PLL.
This commit is contained in:
whitequark 2019-06-03 04:39:05 +00:00
parent 1eee7cd76f
commit 6fae06aea9
6 changed files with 45 additions and 12 deletions
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2
nmigen/test/test_build_dsl.py
View file

@ -17,7 +17,7 @@ class PinsTestCase(FHDLTestCase):
def test_wrong_dir(self):
with self.assertRaises(TypeError,
msg="Direction must be one of \"i\", \"o\" or \"io\", not 'wrong'"):
msg="Direction must be one of \"i\", \"o\", \"oe\", or \"io\", not 'wrong'"):
p = Pins("A0 A1", dir="wrong")

5
nmigen/test/test_build_res.py
View file

@ -197,13 +197,14 @@ class ConstraintManagerTestCase(FHDLTestCase):
def test_wrong_request_with_dir(self):
with self.assertRaises(TypeError,
msg="Direction must be one of \"i\", \"o\", \"io\", or \"-\", not 'wrong'"):
msg="Direction must be one of \"i\", \"o\", \"oe\", \"io\", or \"-\", "
"not 'wrong'"):
user_led = self.cm.request("user_led", 0, dir="wrong")
def test_wrong_request_with_dir_io(self):
with self.assertRaises(ValueError,
msg="Direction of (pins o A0) cannot be changed from \"o\" to \"i\"; direction "
"can be changed from \"io\" to \"i\", from \"io\"to \"o\", or from anything "
"can be changed from \"io\" to \"i\", \"o\", or \"oe\", or from anything "
"to \"-\""):
user_led = self.cm.request("user_led", 0, dir="i")