add more tests to display data driver

fix timing issues with display driver

src/groovylight/hub75.py

@@ -1,4 +1,4 @@
-from amaranth import Module, Cat, Mux, ShapeLike, Signal, Assert, Array
+from amaranth import Module, Cat, Mux, Print, ShapeLike, Signal, Assert, Array
 from amaranth.build import Platform
 from amaranth.lib import wiring, data
 from amaranth.lib.wiring import In, Out
@@ -80,6 +80,63 @@ class SwapBuffer(wiring.Component):
         return m
 
 
+class DisplayClock(wiring.Component):
+    """Generates the display clock automatically with the correct delay
+    when start is asserted. Stops when `done` is strobed.
+
+    Can either be used as a /2 clock divider or a /4 with the `double_fetch` parameter.
+    The startup delay is chosen based on the mode or can be set with `startup_delay`
+    """
+
+    def __init__(self, *, double_fetch: bool = True, startup_delay=None, src_loc_at=0):
+        self.double_fetch = double_fetch
+        if startup_delay is None:
+            self.startup_delay = 4 if double_fetch else 1  # FIXME: choose right values.
+        else:
+            self.startup_delay = startup_delay
+
+        super().__init__(
+            {
+                "start": In(1),
+                "done": In(1),
+                "clk": Out(1),
+            },
+            src_loc_at=src_loc_at,
+        )
+
+    def elaborate(self, platform: Platform) -> Module:
+        m = Module()
+
+        counter = Signal(range(max(self.startup_delay, 2) + 1))
+
+        with m.FSM():
+            with m.State("init"):
+                m.d.sync += [counter.eq(0), self.clk.eq(0)]
+                with m.If(self.start == 1):
+                    m.next = "warmup"
+            with m.State("warmup"):
+                m.d.sync += counter.eq(counter + 1)
+                with m.If(counter == self.startup_delay - 1):
+                    m.next = "run"
+                    m.d.sync += counter.eq(0)
+
+            with m.State("run"):
+                with m.If(self.done == 1):
+                    m.next = "init"
+                if self.double_fetch:
+                    m.d.sync += [
+                        self.clk.eq(~counter[1]),
+                        counter.eq(counter + 1),
+                    ]
+                else:
+                    m.d.sync += [
+                        self.clk.eq(~counter),
+                        counter.eq(~counter),
+                    ]
+
+        return m
+
+
 class Hub75DataDriver(wiring.Component):
     def __init__(
         self,
@@ -117,6 +174,7 @@ class Hub75DataDriver(wiring.Component):
         m = Module()
 
         counter = Signal(32)
+        m.d.sync += counter.eq(counter + 1)
 
         pixnum = Signal(range(self.panel_length), init=self.panel_length - 1)
         if self.double_fetch:
@@ -137,7 +195,7 @@ class Hub75DataDriver(wiring.Component):
                 m.d.sync += [
                     self.done.eq(0),
                     counter.eq(0),
-                    pixnum.eq(pixnum.reset),
+                    pixnum.eq(pixnum.init),
                 ]
                 if self.double_fetch:
                     m.d.sync += pixrow.eq(0)
@@ -145,30 +203,31 @@ class Hub75DataDriver(wiring.Component):
                     m.d.sync += self.bram.en.eq(1)
                     m.next = "prefetch" if self.double_fetch else "writerow"
             with m.State("prefetch"):
-                # TODO: do we need this
+                # Allow the BRAM to settle after being enabled.
+                m.d.sync += counter.eq(0)
                 m.next = "writerow"
 
             with m.State("writerow"):
                 if self.double_fetch:
-                    c = counter[0:1]
-                    with m.If(c == 0):
+                    c = counter[0:2]
+                    with m.If(c == 0b0):
                         m.d.sync += [
                             self.data.rgb0.eq(ram_rgb_slice),
                             pixrow.eq(1),
                         ]
-                    with m.If(c == 1):
-                        m.d.sync += self.data.rgb1.eq(ram_rgb_slice)
-                    with m.If(c == 2):
+                    with m.If(c == 0b01):
                         pass
-
-                    with m.If(c == 3):
+                    with m.If(c == 0b10):
+                        m.d.sync += self.data.rgb1.eq(ram_rgb_slice)
                         m.d.sync += [
-                            counter.eq(0),
                             pixnum.eq(pixnum - 1),
                             pixrow.eq(0),
                         ]
                         with m.If(pixnum == 0):
                             m.next = "done"
+
+                    with m.If(c == 0b11):
+                        m.d.sync += counter.eq(0)
                 else:
                     with m.If(counter[0] == 0):
                         m.d.sync += [
@@ -189,74 +248,6 @@ class Hub75DataDriver(wiring.Component):
         return m
 
 
-class Hub75StringDriver(wiring.Component):
-    """A data driver for Hub75 panels. This accesses the line memory and feeds out the data.
-    It is controlled by a Hub75Coordinator to signal when it should run and what bit of the data
-    it should send.
-    """
-
-    def __init__(self, panel_length: int = 128, *, src_loc_at=0):
-        self.panel_length = panel_length
-        super().__init__(
-            {
-                "bcm_select": In(3),
-                "done": Out(1),
-                "start": In(1),
-                "bram": In(
-                    ReadPort.Signature(
-                        addr_width=ceil_log2(panel_length),
-                        shape=data.ArrayLayout(Rgb666Layout, 2),
-                    )
-                ),
-                "display_out": Out(Hub75Data()),
-            },
-            src_loc_at=src_loc_at,
-        )
-
-    def elaborate(self, platform: Platform) -> Module:
-        m = Module()
-
-        self._counter = counter = Signal(32)  # unused count is optimized out
-        m.d.sync += counter.eq(counter + 1)
-
-        ram_rgb0_slice = self.bram.data[0].channel_slice(self.bcm_select)
-        ram_rgb1_slice = self.bram.data[1].channel_slice(self.bcm_select)
-        m.d.comb += [
-            self.display_out.rgb0.eq(ram_rgb0_slice),
-            self.display_out.rgb1.eq(ram_rgb1_slice),
-        ]
-        m.d.sync += Assert(self.bcm_select < 6)
-
-        pixnum = Signal(range(self.panel_length), init=self.panel_length - 1)
-        m.d.comb += self.bram.addr.eq(pixnum)
-
-        with m.FSM():
-            with m.State("init"):
-                m.d.sync += [
-                    self.done.eq(0),
-                    counter.eq(0),
-                    pixnum.eq(self.panel_length - 1),
-                ]
-                with m.If(self.start == 1):
-                    m.d.sync += self.bram.en.eq(1)
-                    m.next = "writerow"
-            with m.State("writerow"):
-                with m.If(counter[0] == 0):
-                    # do nothing
-                    pass
-
-                with m.If((counter[0] == 1) & (pixnum != 0)):
-                    m.d.sync += pixnum.eq(pixnum - 1)
-
-                with m.Else():
-                    m.next = "done"
-            with m.State("done"):
-                m.d.sync += [self.done.eq(1), self.bram.en.eq(0)]
-                m.next = "init"
-
-        return m
-
-
 class Hub75Coordinator(wiring.Component):
     """A shared-control hub75 driver"""
 
@@ -285,7 +276,9 @@ class Hub75Coordinator(wiring.Component):
         for i in range(self.n_strings):
             sb = SwapBuffer(depth=128, shape=data.ArrayLayout(Rgb666Layout, 2))
             bufs.append(sb)
-            stringdriver = Hub75StringDriver(128)
+            stringdriver = Hub75DataDriver(
+                128, data_shape=Rgb666Layout, double_fetch=False
+            )
             strings.append(stringdriver)
             wiring.connect(m, sb.read_port, stringdriver.bram_port)
             m.d.comb += [

src/groovylight/tests/__init__.py

@@ -0,0 +1,7 @@
+
+import pytest
+
+
+@pytest.fixture()
+def simfixture(request: pytest.FixtureRequest, tmp_path): 
+    pass

src/groovylight/tests/test_hub75.py

@@ -7,9 +7,9 @@ import pytest
 from groovylight.common import Rgb888Layout, Rgb666Layout
 
 from groovylight.hub75 import (
+    DisplayClock,
     Hub75Coordinator,
     Hub75DataDriver,
-    Hub75StringDriver,
     SwapBuffer,
 )
 
@@ -42,65 +42,62 @@ def test_swapbuffer():
         sim.run_until(1e-6 * 1000)
 
 
-def test_stringdriver():
-    # the string driver test must
-    # 1. finish
-    # 2. strobe through all of the data in the array
-    # 3. slice the correct bit from the data.
-    m = Module()
-    m.submodules.dut = dut = Hub75StringDriver()
-    m.submodules.mem = mem = Memory(
-        shape=data.ArrayLayout(Rgb666Layout, 2), depth=128, init=[]
-    )
-    port = mem.read_port()
-
-    wiring.connect(m, port, dut.bram)
-
-    async def testbench(ctx):
-        # select a bit, strobe start, read values, test against known.
-        ctx.set(dut.bcm_select, 5)
-        ctx.set(dut.start, 1)
-        await ctx.tick()
-        ctx.set(dut.start, 0)
-        assert ctx.get(dut.bram.en) == 1
-        pass
-
-    sim = Simulator(m)
-    sim.add_clock(1e-6)
-
-    with sim.write_vcd("output.vcd"):
-        sim.run_until(1e-6 * 1000)
-
-
 def test_datadriver():
     # the string driver test must
     # 1. finish
     # 2. strobe through all of the data in the array
     # 3. slice the correct bit from the data.
+    memdata = [{"red": x, "green": x, "blue": x} for x in range(256)]
     m = Module()
     m.submodules.dut = dut = Hub75DataDriver()
-    m.submodules.mem = mem = Memory(shape=Rgb888Layout, depth=256, init=[])
+    m.submodules.mem = mem = Memory(shape=Rgb888Layout, depth=256, init=memdata)
+    m.submodules.clocker = clocker = DisplayClock()
+    m.d.comb += [
+        clocker.start.eq(dut.start),
+        clocker.done.eq(dut.done),
+    ]
+
     port = mem.read_port()
 
     wiring.connect(m, port, dut.bram)
 
     async def testbench(ctx):
         # select a bit, strobe start, read values, test against known.
-        ctx.set(dut.bcm_select, 5)
+        ctx.set(dut.bcm_select, 7)
         ctx.set(dut.start, 1)
         await ctx.tick()
         ctx.set(dut.start, 0)
         assert ctx.get(dut.bram.en) == 1
+        await ctx.tick().until(dut.done == 1)
+
+    async def rgbtest(ctx):
+        await ctx.tick().until(dut.start == 1)
+        counter = 127
+        bitslice = 7
+        async for _, rgb0, rgb1 in ctx.posedge(clocker.clk).sample(dut.data.rgb0, dut.data.rgb1):
+            assert counter >= 0, "should not do more than 128 clocks"
+            e0 = ctx.get(mem.data[counter << 1])
+            e1 = ctx.get(mem.data[(counter << 1) + 1])
+            print(counter)
+            for r, e in [(rgb0, e0), (rgb1, e1)]:
+                assert r.red == (e.red >> bitslice) & 1
+                assert r.green == (e.green >> bitslice) & 1
+                assert r.blue == (e.blue >> bitslice) & 1
+            counter = counter - 1
+
 
     sim = Simulator(m)
     sim.add_clock(1e-6)
+    sim.add_testbench(testbench)
+    sim.add_testbench(rgbtest, background=True)
 
     with sim.write_vcd("output.vcd"):
-        sim.run_until(1e-6 * 1000)
+        sim.run()
+        # sim.run_until(1e-6 * 4000)
 
 
 @pytest.mark.skip()
-def test_hub75():
+def test_hub75_coordinator():
     m = Module()
     m.submodules.dut = dut = Hub75Coordinator(1)