buffers: Add TX/RX buffer helpers

.gitignore

@@ -0,0 +1 @@
+__pycache__

buffers.py

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+#!/usr/bin/env python
+
+import cocotb
+from cocotb.triggers import *
+from cocotb.result import *
+from cocotb.queue import Queue
+
+class tx_buffer:
+	def __init__(self, dut, prefix):
+		self.queue = Queue()
+		self.queue_start_ev = Event()
+		self.queue_done_ev = Event()
+		self.dut = dut
+		self.prefix = prefix
+		pass
+
+	async def main(self):
+		while True:
+			await self.queue_start_ev.wait()
+			self.queue_start_ev.clear()
+			while not self.queue.empty():
+				data = await self.queue.get()
+				getattr(self.dut, self.prefix + "dv").value = True
+				for byte in data:
+					getattr(self.dut, self.prefix + "d").value = byte
+					await Edge(getattr(self.dut, self.prefix + "da"))
+				getattr(self.dut, self.prefix + "dv").value = False
+				await Edge(getattr(self.dut, self.prefix + "da"))
+			self.queue_done_ev.set()
+
+	async def start(self):
+		await cocotb.start(self.main())
+
+	async def send(self, data, send_now=True, wait=None):
+		if wait is None:
+			wait = send_now
+		self.queue.put_nowait(data)
+		if send_now:
+			self.queue_start_ev.set()
+		if wait:
+			await self.queue_done_ev.wait()
+			self.queue_done_ev.clear()
+
+class rx_buffer:
+	def __init__(self, dut, prefix):
+		self.queue = Queue()
+		self.dut = dut
+		self.prefix = prefix
+
+	async def main(self):
+		while True:
+			d = bytearray(b'')
+			await RisingEdge(getattr(self.dut, self.prefix + "a"))
+			while True:
+				await First(Edge(getattr(self.dut, self.prefix + "dt")), Edge(getattr(self.dut, self.prefix + "a")))
+				if not getattr(self.dut, self.prefix + "a").value:
+					break
+				d.append(getattr(self.dut, self.prefix + "d").value)
+			self.queue.put_nowait(d)
+
+	async def start(self):
+		await cocotb.start(self.main())