I was able to get the SWO connected to my FTDI pretty easily. The ST-Link V3Set has the SWO coming out to a couple different pins so I hooked up my scope and found that my SWO data rate was 2M Baud. Note that I am connected to a custom PCB with a STM32F427 with the SWO lined connected to the programming connector.
Once I knew the correct data rate, I simply connected the ST-Link's SWO, VCC, and GND:
to the brainstem(FTDI -> USB) like so:
I used CoolTerm (on Mac) and connected to the USB device for the brainstem, connected and voila!:
Notice that there's an SWO control character between each log character. I know there are some utilities out there to cope with that, but it seem simple enough just for me to modify my existing python serial view script that I use inside Clion and skip over that character. A more robust handling can come later, but for now I'm getting this:
Here's the python script I use (note that "import serial" is for pyserial). Note that it color codes if you format your log statements as you see in my screenshot.
import signal
import serial
import sys
import argparse
import re
class Color:
WHITE = '\x1b[0;30m'
RED = '\x1b[0;31m'
GREEN = '\x1b[0;32m'
YELLOW = '\x1b[0;33m'
BLUE = '\x1b[0;34m'
PURPLE = '\x1b[0;35m'
TEAL = '\x1b[0;36m'
DARK_GRAY = '\x1b[0;37m'
LIGHT_GRAY = '\x1b[0;38m'
BOLD_WHITE = '\x1b[1;30m'
BOLD_RED = '\x1b[1;31m'
BOLD_GREEN = '\x1b[1;32m'
BOLD_YELLOW = '\x1b[1;33m'
BOLD_BLUE = '\x1b[1;34m'
BOLD_PURPLE = '\x1b[1;35m'
BOLD_TEAL = '\x1b[1;36m'
BOLD_DARK_GRAY = '\x1b[1;37m'
BOLD_LIGHT_GRAY = '\x1b[1;38m'
class ConnectionState:
DISCONNECTED = 1
CONNECTING = 2
CONNECTED = 3
global connectionState
def signal_handler(signal, frame):
global interrupted
interrupted = True
signal.signal(signal.SIGINT, signal_handler)
def stream(device, baudrate):
global interrupted
interrupted = False
colorDict = {
'A' : Color.BOLD_TEAL,
'V' : Color.DARK_GRAY,
'D' : Color.LIGHT_GRAY,
'I' : Color.LIGHT_GRAY,
'S' : Color.BOLD_BLUE,
'R' : Color.BOLD_GREEN,
'W' : Color.BOLD_YELLOW,
'E' : Color.BOLD_RED,
}
global connectionState
if connectionState == ConnectionState.DISCONNECTED:
connectionState = ConnectionState.CONNECTING
sys.stdout.write(Color.BOLD_PURPLE)
print('Connecting to %s at %d baud...' % (device, baudrate))
with serial.Serial(port=device, baudrate=baudrate, timeout=0.5) as ser:
regex = re.compile(r"^.* [0-9] ([AVDISRWE]).+[:]")
if connectionState == ConnectionState.CONNECTING:
connectionState = ConnectionState.CONNECTED
print('Connected')
exceptionCount = 0
lineBuffer = ""
while not interrupted:
try:
char = ser.read(1)
if char:
#For now just skip over the SWO byte. A more robust solution would/could do something
#with these other than skip them. But for now, this yields printf style logging
if char != b'\x01':
lineBuffer += char.decode('windows-1252')
if char == b'\n':
match = regex.search(lineBuffer)
if match and match.group(1):
color = colorDict.get(match.group(1), None)
if color:
sys.stdout.write(color)
sys.stdout.write(lineBuffer)
sys.stdout.flush()
lineBuffer = ""
except Exception as e:
raise e
def main():
# global interrupted
parser = argparse.ArgumentParser(description='Stream serial port to stdout')
parser.add_argument('device', nargs=1, type=str, help='the device to stream')
parser.add_argument('-b', '--baud', nargs=1, type=int, help='baud rate', required=False, default=2000000)
args = parser.parse_args()
global connectionState
connectionState = ConnectionState.DISCONNECTED
global interrupted
interrupted = False
while not interrupted:
try:
stream(args.device[0], args.baud)
except:
if connectionState == ConnectionState.CONNECTED:
connectionState = ConnectionState.DISCONNECTED
sys.stdout.write(Color.BOLD_PURPLE)
print('Disconnected')
if __name__ == "__main__":
main()
You'll probably want to modify it to your liking.
Hope others find this useful.
Craig
