Written by whitequark, 2019.

diff --git a/software/glasgow/access/direct/demultiplexer.py b/software/glasgow/access/direct/demultiplexer.py
index 3df8c2e..068b40e 100644
--- a/software/glasgow/access/direct/demultiplexer.py
+++ b/software/glasgow/access/direct/demultiplexer.py
@@ -30,7 +30,7 @@ from .. import AccessDemultiplexer, AccessDemultiplexerInterface
 #
 # To deal with this, use requests of at most 1024 EP buffer sizes (512 KiB with the FX2) as
 # an arbitrary cutoff, and hope for the best.
-_max_packets_per_ep = 1024
+_max_packets_per_ep = 2048
 
 # USB has the limitation that all transactions are host-initiated. Therefore, if we do not queue
 # reads for the IN endpoints quickly enough, the HC will not even poll the device, and the buffer
@@ -52,7 +52,7 @@ _max_packets_per_ep = 1024
 # To try and balance these effects, we choose a medium buffer size that should work well with most
 # applications. It's possible that this will need to become customizable later, but for now
 # a single fixed value works.
-_packets_per_xfer = 32
+_packets_per_xfer = 512
 
 # Queue as many transfers as we can, but no more than 10, as the returns beyond that point
 # are diminishing.
diff --git a/software/glasgow/applet/all.py b/software/glasgow/applet/all.py
index 35b8960..3f37b9f 100644
--- a/software/glasgow/applet/all.py
+++ b/software/glasgow/applet/all.py
@@ -44,3 +44,5 @@ from .video.rgb_input import VideoRGBInputApplet
 from .video.vga_output import VGAOutputApplet
 from .video.vga_terminal import VGATerminalApplet
 from .video.ws2812_output import VideoWS2812OutputApplet
+
+from .logic import LogicApplet
diff --git a/software/glasgow/applet/logic.py b/software/glasgow/applet/logic.py
new file mode 100644
index 0000000..483e99e
--- /dev/null
+++ b/software/glasgow/applet/logic.py
@@ -0,0 +1,95 @@
+import sys
+import logging
+import os
+import asyncio
+from nmigen.compat import *
+from nmigen.compat.genlib.cdc import MultiReg
+
+from . import *
+
+
+class LogicSubtarget(Module):
+    def __init__(self, pads, in_fifo):
+        input = Signal.like(pads.d_t.i)
+        latch = Signal.like(pads.d_t.i)
+        self.submodules += MultiReg(pads.d_t.i, input)
+
+        self.comb += [
+            in_fifo.din[0:4].eq(input[0:4]),
+            in_fifo.din[4:8].eq(latch[0:4]),
+        ]
+
+        self.submodules.fsm = FSM()
+        self.fsm.act("CAPTURE-1",
+            NextValue(latch, input),
+            NextState("CAPTURE-2")
+        )
+        self.fsm.act("CAPTURE-2",
+            in_fifo.we.eq(1),
+            If(in_fifo.writable,
+                NextState("CAPTURE-1")
+            ).Else(
+                NextState("OVERFLOW")
+            )
+        )
+        self.fsm.act("OVERFLOW",
+            NextState("OVERFLOW")
+        )
+
+
+async def async_stdout(limit=asyncio.streams._DEFAULT_LIMIT, loop=None):
+    if loop is None:
+        loop = asyncio.get_event_loop()
+
+    writer_transport, writer_protocol = await loop.connect_write_pipe(
+        lambda: asyncio.streams.FlowControlMixin(loop=loop),
+        os.fdopen(sys.stdout.fileno(), "wb"))
+    writer = asyncio.streams.StreamWriter(
+        writer_transport, writer_protocol, None, loop)
+
+    return writer
+
+
+class LogicApplet(GlasgowApplet, name="logic"):
+    logger = logging.getLogger(__name__)
+    preview = True
+
+    @classmethod
+    def add_build_arguments(cls, parser, access):
+        super().add_build_arguments(parser, access)
+
+        access.add_pin_set_argument(parser, "d", required=True, width=range(5))
+
+    def build(self, target, args):
+        self.mux_interface = iface = target.multiplexer.claim_interface(self, args)
+        iface.add_subtarget(LogicSubtarget(
+            pads=iface.get_pads(args, pin_sets=("d",)),
+            in_fifo=iface.get_in_fifo(auto_flush=False, depth=16384),
+        ))
+
+    @classmethod
+    def add_run_arguments(cls, parser, access):
+        super().add_run_arguments(parser, access)
+
+    async def run(self, device, args):
+        return await device.demultiplexer.claim_interface(self, self.mux_interface, args)
+
+    @classmethod
+    def add_interact_arguments(cls, parser):
+        pass
+
+    async def interact(self, device, args, iface):
+        output_stream = await async_stdout()
+        while True:
+            data = await iface.read(65536)
+            output_stream.write(data)
+            if output_stream.is_closing():
+                print("glasgow: stdout closed, terminating", file=sys.stderr)
+                return
+
+# ------------------------------------------------------------------------------------------------
+
+class LogicAppletTestCase(GlasgowAppletTestCase, applet=LogicApplet):
+    @synthesis_test
+    def test_build(self):
+        self.assertBuilds()