I need to debug a serial protocol between two embedded microcontrollers.
Between them there's a serial line compatible with my FT2232h mini-module.
Situation is very similar to what described in this question except:
- lines are driven at 3.3V (not 5V).
- development station is running Linux (not windows).
- I have lower timing requirements (more-or-less I care only about actual sequence and very large delays).
- Baud-rate is "standard" 115200.
I could write my own monitor program, but I'm very surprised my search did not give results.
---delete---Can someone suggest which (possibly free) project can help me?---
UPDATE: I didn't find anything suitable, so I started writing a simple monitor in python (current source below). This more-or-less works, but it still seem to buffer chars so that a sequence like:
- rqst1 -->
- <-- ack1
- rqst2 -->
- <-- ack2
MIGHT end up written as:
I do not know if buffering is done at FT2232H, USB, Linux driver or Python level (possibly at several levels!).
Is there any way I can force "no buffering" in the code below? (before I start to rewriting the whole crap in plain C for speed).
#!/usr/bin/python3
import serial, time, sys, threading
from colorama import Fore, Style, init as colorama_init
from binascii import hexlify
colorama_init()
# lock to serialize console output
lock = threading.Lock()
class Highlight:
def __init__(self, clazz, color):
self.color = color
self.clazz = clazz
def __enter__(self):
print(self.color, end="")
def __exit__(self, type, value, traceback):
if self.clazz == Fore:
print(Fore.RESET, end="")
else:
assert self.clazz == Style
print(Style.RESET_ALL, end="")
sys.stdout.flush()
if len(sys.argv) != 3 and len(sys.argv) != 4:
sys.stderr.write("Usage: %s <baud> <port1> [<port2>]\n" % (sys.argv[0]))
exit(1)
def open_serial(port, baud):
ser = serial.Serial()
ser.port = port
ser.baudrate = baud
ser.bytesize = serial.EIGHTBITS # number of bits per bytes
ser.parity = serial.PARITY_NONE # set parity check: no parity
ser.stopbits = serial.STOPBITS_ONE # number of stop bits
# ser.timeout = None #block read
ser.timeout = 0 # non blocking read
ser.xonxoff = False # disable software flow control
ser.rtscts = False # disable hardware (RTS/CTS) flow control
ser.dsrdtr = False # disable hardware (DSR/DTR) flow control
ser.writeTimeout = 2 # timeout for write
try:
ser.open()
except Exception as e:
print("error open serial port: " + str(e))
exit()
return ser
def sprint(c, color):
if len(c) > 0:
print(color)
h = hexlify(c)
h += b' ' * (120 - len(h))
s = bytes(x if 31 < x < 128 else 46 for x in c)
with lock:
sys.stdout.buffer.write(h)
sys.stdout.buffer.write(s)
sys.stdout.flush()
s1 = open_serial(sys.argv[2], sys.argv[1])
s2 = open_serial(sys.argv[3], sys.argv[1])
running = True
try:
while running:
n = s1.in_waiting
if n > 0:
c = s1.read(n)
sprint(c, Fore.CYAN)
n = s2.in_waiting
if n > 0:
c = s2.read(n)
sprint(c, Fore.GREEN)
except Exception as e1:
print("error communicating...: " + str(e1))
s1.close()
s2.close()
except KeyboardInterrupt:
exit()
