TL;DR:

I need to read the time off of my Hologram Nova USB cellular modem on /dev/ttyACM0 and update the system clock after the pi restarts. I'd like to do it in Python but it isn't reading the serial tty correctly.

My build

• I'm running python 2.7.13 on Raspbian 9
• I'm using pyserial 3.2.1-1
• I have a Pi 3 b+
• The modem is a USB connected U-Blox SARA-U201 (AKA Hologram Nova)

What works so far:

• My cellular modem is sitting on /dev/ttyACM0
• I can communicate with it using screen /dev/ttyacm0 9600
• I can get a time stamp in the screen session by typing AT+CCLK? and hitting Enter

Here is the output from the screen session

AT+CCLK?

+CCLK: "19/05/16,21:31:47-16"

OK

What doesn't work so far:

• I have tried to use pyserial to interrogate the tty and return the time stamp.
• I have tried to create an expect script using screen
• I'd prefer not to do this with an expect script when python is a lot better.
• I'll post my source for expect if this can't be done in Python.

Python Code:

import serial import time, sys import datetime response = '' SERIAL_PORT = "/dev/ttyACM0" ser = serial.Serial(SERIAL_PORT, baudrate = 9600, timeout = 5) ser.write("AT+CCLK?\r") response = ser.readline() print response 

When using the python console the line ser.write("AT+CCLK?\r") results in a 9 being returned on the next line. response remains empty and ser.inWaiting() is equal to 0. For further clarification here is a screenshot of my attempt to query the modem:

TL;DR:

I need to read the time off of my Hologram Nova USB cellular modem on /dev/ttyACM0 and update the system clock after the pi restarts. I'd like to do it in Python but it isn't reading the serial tty correctly.

My build

• I'm running python 2.7.13 on Raspbian 9
• I'm using pyserial 3.2.1-1
• I have a Pi 3 b+
• The modem is a USB connected U-Blox SARA-U201 (AKA Hologram Nova)

What works so far:

• My cellular modem is sitting on /dev/ttyACM0
• I can communicate with it using screen /dev/ttyacm0 9600
• I can get a time stamp in the screen session by typing AT+CCLK? and hitting Enter

Here is the output from the screen session

AT+CCLK?

+CCLK: "19/05/16,21:31:47-16"

OK

What doesn't work so far:

• I have tried to use pyserial to interrogate the tty and return the time stamp.
• I have tried to create an expect script using screen
• I'd prefer not to do this with an expect script when python is a lot better.
• I'll post my source for expect if this can't be done in Python.

Python Code:

import serial import time, sys import datetime response = '' SERIAL_PORT = "/dev/ttyACM0" ser = serial.Serial(SERIAL_PORT, baudrate = 9600, timeout = 5) ser.write("AT+CCLK?\r") response = ser.readline() print response 

When using the python console the line ser.write("AT+CCLK?\r") results in a 9 being returned on the next line. response remains empty and ser.inWaiting() is equal to 0. Here is the text returned from the tty:

root@raspberrypi:/home/pi# python Python 2.7.13 (default, Sep 26 2018, 18:42:22) [GCC 6.3.0 20170516] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import serial >>> import time, sys >>> import datetime >>> response = '' >>> SERIAL_PORT = "/dev/ttyACM0" >>> ser = serial.Serial(SERIAL_PORT, baudrate = 9600, timeout = 5) >>> ser.write("AT+CCLK?\r") 9 >>> response = ser.readline() >>> print response 

TL;DR:

I need to read the time off of my Hologram Nova USB cellular modem on /dev/ttyACM0 and update the system clock after the pi restarts. I'd like to do it in Python but it isn't reading the serial tty correctly.

My build

• I'm running python 2.7.13 on Raspbian 9
• I'm using pyserial 3.2.1-1
• I have a Pi 3 b+
• The modem is a USB connected U-Blox SARA-U201 (AKA Hologram Nova)

What works so far:

• My cellular modem is sitting on /dev/ttyACM0
• I can communicate with it using screen /dev/ttyacm0 9600
• I can get a time stamp in the screen session by typing AT+CCLK? and hitting Enter

Here is the output from the screen session

AT+CCLK?

+CCLK: "19/05/16,21:31:47-16"

OK

What doesn't work so far:

• I have tried to use pyserial to interrogate the tty and return the time stamp.
• I have tried to create an expect script using screen
• I'd prefer not to do this with an expect script when python is a lot better.
• I'll post my source for expect if this can't be done in Python.

Python Code:

import serial import time, sys import datetime response = '' SERIAL_PORT = "/dev/ttyACM0" ser = serial.Serial(SERIAL_PORT, baudrate = 9600, timeout = 5) ser.write("AT+CCLK?\r") response = ser.read(30) print response 

When using the python console the line ser.write("AT+CCLK?\r") results in a 9 being returned on the next line. response remains empty and ser.inWaiting() is equal to 0.

TL;DR:

I need to read the time off of my Hologram Nova USB cellular modem on /dev/ttyACM0 and update the system clock after the pi restarts. I'd like to do it in Python but it isn't reading the serial tty correctly.

My build

• I'm running python 2.7.13 on Raspbian 9
• I'm using pyserial 3.2.1-1
• I have a Pi 3 b+
• The modem is a USB connected U-Blox SARA-U201 (AKA Hologram Nova)

What works so far:

• My cellular modem is sitting on /dev/ttyACM0
• I can communicate with it using screen /dev/ttyacm0 9600
• I can get a time stamp in the screen session by typing AT+CCLK? and hitting Enter

Here is the output from the screen session

AT+CCLK?

+CCLK: "19/05/16,21:31:47-16"

OK

What doesn't work so far:

• I have tried to use pyserial to interrogate the tty and return the time stamp.
• I have tried to create an expect script using screen
• I'd prefer not to do this with an expect script when python is a lot better.
• I'll post my source for expect if this can't be done in Python.

Python Code:

import serial import time, sys import datetime response = '' SERIAL_PORT = "/dev/ttyACM0" ser = serial.Serial(SERIAL_PORT, baudrate = 9600, timeout = 5) ser.write("AT+CCLK?\r") response = ser.readline() print response 

When using the python console the line ser.write("AT+CCLK?\r") results in a 9 being returned on the next line. response remains empty and ser.inWaiting() is equal to 0. For further clarification here is a screenshot of my attempt to query the modem: