这个开发板需要SIM卡联网，官方的demo又有点问题，踩了坑，标记下

import utime   # 延时函数在utime库中
import modem
from modem import net
from modem import sim
deviceName = modem.info.getDevImei()
# net.setModem(0) #开启全功能模式
print("deviceName:", deviceName)
print("设备ID:", modem.info.getDevProductId())
print("固件版本:", modem.info.getDevFwVersion())
print("信号强度：",net.getCsq())
print('网络模式：',net.getMode())
print('工作状态：',net.getModem())
print("获取邻近 CELL 的信息:",net.getCellInfo())

print("IMSI:",sim.getImsi())
print("SIM卡信息:",sim.getIccid())
print("SIM卡状态：",sim.getStatus())


import http

data_post = {
    'url': 'http://httpbin.org/get',
    'method': 'GET',
    'headers': {
        'Content-Type':'application/json'
    },
    'timeout': 30000,
    'params': ''
}

def cb(data):
    print("联网变量：",g_connect_status)
    print(data)


import network

g_connect_status = False
def connect_network():
    global g_connect_status
    netw = network.NetWorkClient()
    if netw._stagecode is not None and netw._stagecode == 3 and netw._subcode == 1:
        g_connect_status = True
        print("已联网，信号强度：", net.getCsq())
        http.request(data_post, cb)
        # netw.on(1,on_4g_cb)
        # netw.connect(None)
    else:
        print('network register failed')

connect_network()#连接网络

# http.request(data_post, cb)

if __name__ == '__main__':
    while True:             # 无限循环
        print("helloworld")  # 打印"helloworld"字串到console中
        utime.sleep(1)      # 打印完之后休眠1秒