如何使用PyCom FiPy接入长期演进蜂窝网络？

Question

我正在尝试使PyCom FiPy板与LTE网络连接工作。我有全息SIM卡。我使用了两段代码。一个来自PyCom docs，另一个来自我在PyCom调试LTE论坛上找到的代码。

来自PyCom LTE文档的第一个代码片段

import time
from network import LTE

print('main-testy.py starting.  This is the code snippet from pycom docs')

#lte = LTE(carrier="verizon")
lte = LTE()


print("trying to attach")
lte.attach(band=13)
while not lte.isattached():
    time.sleep(0.5)
    print('Attaching...')

print("trying to connect")
lte.connect(cid=3)
while not lte.isconnected():
    time.sleep(0.5)
    print('Connecting...')

# Now use sockets as usual...

输出

最初几次我运行这段代码时，它会附加，然后在lte.connect调用中生成一个python错误。最初的样本使用的是“verizon”运营商，但论坛上的一篇帖子称这不是必要的。

>>> Running main-testy.py

>>> 
>>> 
main-testy.py starting.  This is the code snippet from pycom docs
trying to attach
Attaching...
Attaching...
Attaching...
.. never attaches

来自PyCom LTE论坛帖子的第二个代码片段

浏览论坛，我发现其他一些用户也有类似的问题。我将他们的尝试与文档中的一些可用命令结合起来，编写了这段代码。它提供了一些关于simcard和调制解调器的基本信息。以下是代码。

# Determine carrier notes
from network import LTE


# 1817



lte = LTE()

def send_at_cmd_pretty(cmd):
    response = lte.send_at_cmd(cmd).split('\r\n')
    for line in response:
        print(line)


print("get phy status")
send_at_cmd_pretty('AT!="showphy"')     # get the PHY status
print("get System FSM")
send_at_cmd_pretty('AT!="fsm"')         # get the System FSM
print("get System COPS.  PLMN Selection: +COPS")
print("!!!!!!!!!1 always generates error !!!!!!!!!!!!")
send_at_cmd_pretty('AT+COPS=?')         # get the System FSM


print("get conformance test modes. List of carriers? ")
send_at_cmd_pretty("AT+SQNCTM=?")       # get list of carriers for
# results are
# "3gpp-conformance", "att", "docomo", "kt", "lgu", "softbank", "standard", "telstra", "verizon")

results = lte.imei()
print("lte.imei results \n{}" . format(results))


results = lte.iccid()
print("lte.iccid results \n{}" . format(results))

输出

所有这些代码都会运行，但其中一个命令(+COPS)会给出错误。我确实检查了AT命令参考，语法是+COPYS=？看起来是正确的。也许这个特定的命令只能在附加后才能发出。

>> Running lte-basic-operations.py

>>> 
>>> 
get phy status

DL SYNCHRO STATISTICS
=====================
    Synchro state                         : OFF
    PPU SIB1 ACQ watchdog                 : 0
    Frequency Hypothesis RF  (Hz)         : 0
    RSRP (dBm)                            : 0.00
    RSRQ  (dB)                            : 0.00
    Channel estimation state (Cell-spec.) : LOW CINR
    Channel estimation state (UE-spec.)   : LOW CINR
    Channel estimation state (MBSFN)      : LOW CINR
    Channel estimation CINR               : 0.00
    Channel length                        : SHORT
  AGC
    AGC RX gain (dB)                      : 0.00
    RX PSD BO (dBFs)                      : 0.00
    RX PSD (dBm)                          : 0.00
    Noise level RS (dBm)                  : 0.00
    Digital gain (dB)                     : 0.00
    CINR RS (dB)                          : 0.00
  NARROWBANDS
    Last DL NB                            : 0
    Last UL NB                            : 0
  AFC
    Frequency offset RF  (Hz)             : 0
    Frequency offset BB  (Hz)             : 0
  PBCH
    MIB received quantity                 : 0
    MIB timeout quantity                  : 0

OK

get System FSM

SYSTEM FSM
==========
    +--------------------------+--------------------+
    |            FSM           |        STATE       |
    +--------------------------+--------------------+
    | RRC TOP FSM              |STOPPED             |
    | RRC SEARCH FSM           |NULL                |
    | RRC ACTIVE FSM           |NULL                |
    | PMM PLMN FSM             |NULL                |
    | EMM MAIN FSM             |NULL                |
    | EMM AUTH FSM             |NULL                |
    | EMM CONN FSM             |NULL                |
    | EMM TAU FSM              |NULL                |
    | EMM TEST FSM             |NULL                |
    | ESM BEARER FSM           |BEARER_NULL         |
    | SMS MT FSM               |IDLE                |
    | SMS MO FSM               |IDLE                |
    | HP MAIN FSM              |IDLE                |
    | HP USIM FSM              |NULL                |
    | HP SMS MO FSM            |IDLE                |
    | HP SMS MT FSM            |IDLE                |
    | HP CAT FSM               |NULL                |
    +--------------------------+--------------------+

OK

get System COPS.  PLMN Selection: +COPS
!!!!!!!!!1 always generates error !!!!!!!!!!!!

ERROR

get conformance test modes. List of carriers? 

+SQNCTM: ("3gpp-conformance", "att", "docomo", "kt", "lgu", "softbank", "standard", "telstra", "verizon")

OK

lte.imei results 
354346095554902
lte.iccid results 
8944500208186565235
>

Answer 1

我确实设法让LTE与全息图卡一起工作。然而，它并不是100%可靠的。有时它会停滞或挂起。任何意见都是值得感谢的。

import time
from network import LTE
import utime
import machine
import _thread

print('main-testy.py starting.  This is the code snippet from pycom docs')

def send_at_cmd_pretty(cmd):
    response = lte.send_at_cmd(cmd).split('\r\n')
    for line in response:
        print(line)

def do_ntp(a_server):
    # Syncing time
    RTCI = machine.RTC()
    print('Syncing time with %s' % a_server, end='')
    RTCI.ntp_sync(a_server)
    while not RTCI.synced():
        print('.', end='')
        utime.sleep(1)
    print('')

def get_time_as_string():
    year, month, mday, hour, minute, second, weekday, yearday = utime.localtime()
    # form an iso time string
    # eg. 1985-12-04T23:20:50
    a_string = '{}-{:02d}-{:02d}T{:02d}:{:02d}:{:02d}' . format(year, month, mday, hour, minute, second)
    return a_string


###############################################


lte = LTE()
lte.reset()
lte.init()



print("trying to attach")
#lte.attach(band=13)
lte.attach()
while not lte.isattached():
    time.sleep(0.5)
    #print('Attaching...')
    print('Attaching...', end='')
    send_at_cmd_pretty('AT+CEREG?')         # get the System FSM

time.sleep(5)


print("trying to connect")
#lte.connect(cid=3)
lte.connect()
while not lte.isconnected():
    time.sleep(0.5)
    print('Connecting...')

time.sleep(5)



# Now use sockets as usual...
print('**** connected ***********************')


do_ntp('time.google.com')
#do_ntp('pool.ntp.org')
time.sleep(5)
print(get_time_as_string())

Answer 2

当使用全息SIM卡时，您不应该使用Verizon配置文件，因为这只适用于Verizon SIM卡。此外，对于全息图，CID应为1，3仅适用于Verizon SIM卡。

即使ICCID命令返回结果，SIM卡似乎也有问题，因为HP USIM FSM报告NULL。

您可以先尝试lte.factory_reset()，然后再使用cid=1重试吗？

如果问题仍然存在，请联系Pycom support https://pycom.io/community/contact-support/