From 2b501347f62e5a7e59bb22d1e7f70128c1dffdbb Mon Sep 17 00:00:00 2001
From: Martin Teichmann <martin.teichmann@gmail.com>
Date: Wed, 1 Feb 2023 09:42:02 +0000
Subject: [PATCH] improve addressing random terminals
if the status of the bus is unknown, we need to assure not
to address two terminals at the same time
---
ebpfcat/ethercat.py | 18 ++++++++++++++++--
ebpfcat/scripts.py | 20 ++++++++++----------
2 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/ebpfcat/ethercat.py b/ebpfcat/ethercat.py
index 4354262..2214772 100644
--- a/ebpfcat/ethercat.py
+++ b/ebpfcat/ethercat.py
@@ -28,6 +28,7 @@ this modules contains the code to actually talk to EtherCAT terminals.
"""
from asyncio import ensure_future, Event, Future, gather, get_event_loop, Protocol, Queue, Lock
from enum import Enum
+from itertools import count
from random import randint
from socket import socket, AF_PACKET, SOCK_DGRAM
from struct import pack, unpack, unpack_from, calcsize
@@ -281,7 +282,12 @@ class EtherCat(Protocol):
if packet.full() or self.send_queue.empty():
data = await self.roundtrip_packet(packet)
for start, stop, future in dgrams:
- future.set_result(data[start:stop])
+ wkc, = unpack("<H", data[stop:stop+2])
+ if wkc == 0:
+ future.set_exception(
+ RuntimeError("datagram was not processed"))
+ else:
+ future.set_result(data[start:stop])
dgrams = []
packet = Packet()
@@ -355,6 +361,15 @@ class EtherCat(Protocol):
no, = unpack("<h", ret[16:18]) # number of terminals
return no
+ async def find_free_address(self):
+ """Find an absolute address currently not in use"""
+ no = await self.count()
+ for i in count(no):
+ try:
+ await self.roundtrip(ECCmd.FPRD, i, 0x10, "H", 0)
+ except RuntimeError:
+ return i # this address is not in use
+
def connection_made(self, transport):
"""start the send loop once the connection is made"""
transport.get_extra_info("socket").bind(self.addr)
@@ -456,7 +471,6 @@ class Terminal:
async def parse(func):
bitpos = 0
async for idx, subidx, sm, bits in func:
- #print("k", idx, subidx, sm, bits)
if idx == 0:
pass
elif bits < 8:
diff --git a/ebpfcat/scripts.py b/ebpfcat/scripts.py
index 4a2ecd0..689b428 100644
--- a/ebpfcat/scripts.py
+++ b/ebpfcat/scripts.py
@@ -43,17 +43,17 @@ async def info():
if args.terminal is None:
terminals = range(await ec.count())
+ terms = [Terminal() for t in terminals]
+ for t in terms:
+ t.ec = ec
+ await asyncio.gather(*(t.initialize(-i, i + 7)
+ for i, t in zip(terminals, terms)))
else:
- # former terminal: don't listen!
- # this does not work with all terminals, dunno why
- await ec.roundtrip(ECCmd.FPRW, 7, 0x10, "H", 0)
- terminals = [args.terminal]
-
- terms = [Terminal() for t in terminals]
- for t in terms:
- t.ec = ec
- await asyncio.gather(*(t.initialize(-i, i + 7)
- for i, t in zip(terminals, terms)))
+ free = await ec.find_free_address()
+ term = Terminal()
+ term.ec = ec
+ await term.initialize(-args.terminal, free)
+ terms = [term]
for i, t in enumerate(terms):
print(f"terminal no {i}")
--
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