はじめに
NuttXはRNDISドライバを持っている。
STM32F4DiscoveryはRNDISドライバを使用すると、USBでEthernetデバイスとして通信できるようになる。
意外なほど簡単に使用することができる。
コンフィグレーション
$ tools/configure.sh -l configs/stm32f4discovery/rndis
動作確認
STM32F4Discovery側
初期状態では、デバイスは認識しているがIPアドレスは振られていない。
nsh> ifconfig
eth0 Link encap:Ethernet HWaddr 00:e0:de:ad:ca:fe at UP
inet addr:0.0.0.0 DRaddr:0.0.0.0 Mask:0.0.0.0
lo Link encap:Local Loopback at UP
inet addr:127.0.0.1 DRaddr:127.0.0.1 Mask:255.0.0.0
IPv4 TCP UDP ICMP
Received 0008 0000 0008 0000
Dropped 0000 0000 0000 0000
IPv4 VHL: 0000 Frg: 0000
Checksum 0000 0000 0000 ----
TCP ACK: 0000 SYN: 0000
RST: 0000 0000
Type 0000 ---- ---- 0000
Sent 0005 0000 0005 0000
Rexmit ---- 0000 ---- ----
次のコマンドでIPアドレスを割り当てる。
nsh> ifconfig eth0 192.168.20.100
IPアドレスを指定すると、ネットマスクとゲートウェイは自動的に設定される。
nsh> ifconfig
eth0 Link encap:Ethernet HWaddr 00:e0:de:ad:ca:fe at UP
inet addr:192.168.20.100 DRaddr:192.168.20.1 Mask:255.255.255.0
lo Link encap:Local Loopback at UP
inet addr:127.0.0.1 DRaddr:127.0.0.1 Mask:255.0.0.0
IPv4 TCP UDP ICMP
Received 0016 0000 0016 0000
Dropped 0000 0000 0000 0000
IPv4 VHL: 0000 Frg: 0000
Checksum 0000 0000 0000 ----
TCP ACK: 0000 SYN: 0000
RST: 0000 0000
Type 0000 ---- ---- 0000
Sent 0011 0000 0011 0000
Rexmit ---- 0000 ---- ----
PC側
RNDISを有効化してSTM32F4DiscoveryのマイクロUSBとPCのUSBポートを接続すると、 次のように認識される。
$ dmesg ...(snip)... [187044.300595] usb 1-7.4: new full-speed USB device number 9 using xhci_hcd [187044.646579] usb 1-7.4: New USB device found, idVendor=584e, idProduct=5342 [187044.646584] usb 1-7.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [187044.646586] usb 1-7.4: Product: RNDIS gadget [187044.646588] usb 1-7.4: Manufacturer: NuttX [187044.646590] usb 1-7.4: SerialNumber: 1234 [187044.672267] usbcore: registered new interface driver cdc_ether [187044.674191] rndis_host 1-7.4:1.0: skipping garbage [187044.689562] rndis_host 1-7.4:1.0: dev can't take 1558 byte packets (max 660), adjusting MTU to 602 [187044.739995] rndis_host 1-7.4:1.0 eth0: register 'rndis_host' at usb-0000:15:00.0-7.4, RNDIS device, a0:e0:de:ad:ca:fe [187044.740051] usbcore: registered new interface driver rndis_host [187044.744102] usbcore: registered new interface driver rndis_wlan [187044.752038] rndis_host 1-7.4:1.0 enxa0e0deadcafe: renamed from eth0
enxa0e0deadcafeというネットワークデバイスとして見えている。
これもIPアドレスは振られていないので、ネットワーク設定画面で192.168.20.1に設定する。
pingが通ればOK。
$ ping 192.168.20.100 PING 192.168.20.100 (192.168.20.100) 56(84) bytes of data. 64 bytes from 192.168.20.100: icmp_seq=2 ttl=64 time=0.472 ms 64 bytes from 192.168.20.100: icmp_seq=3 ttl=64 time=0.460 ms 64 bytes from 192.168.20.100: icmp_seq=4 ttl=64 time=0.446 ms 64 bytes from 192.168.20.100: icmp_seq=5 ttl=64 time=0.438 ms
ついでにSTM32F4Discovery側からpingも確認しておく。
nsh> ping 192.168.20.1 PING 192.168.20.1 56 bytes of data 56 bytes from 192.168.20.1: icmp_seq=0 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=1 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=2 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=3 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=4 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=5 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=6 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=7 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=8 time=0 ms 56 bytes from 192.168.20.1: icmp_seq=9 time=0 ms 10 packets transmitted, 10 received, 0% packet loss, time 10100 ms
MQTT
Ethernetが使えるので当然MQTTも使えるはず。
前回の要領でMQTTを有効化する。
nsh> ifconfig eth0 192.168.20.100
nsh> ifconfig
eth0 Link encap:Ethernet HWaddr 00:e0:de:ad:ca:fe at UP
inet addr:192.168.20.100 DRaddr:192.168.20.1 Mask:255.255.255.0
lo Link encap:Local Loopback at UP
inet addr:127.0.0.1 DRaddr:127.0.0.1 Mask:255.0.0.0
IPv4 TCP UDP ICMP
Received 0039 0000 0001 0000
Dropped 0002 0000 0000 0000
IPv4 VHL: 0002 Frg: 0000
Checksum 0000 0000 0000 ----
TCP ACK: 0000 SYN: 0000
RST: 0000 0000
Type 0000 ---- ---- 0000
Sent 0002 0000 0002 0000
Rexmit ---- 0000 ---- ----
nsh> ping 192.168.20.1
PING 192.168.20.1 56 bytes of data
56 bytes from 192.168.20.1: icmp_seq=0 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=1 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=2 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=3 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=4 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=5 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=6 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=7 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=8 time=0 ms
56 bytes from 192.168.20.1: icmp_seq=9 time=0 ms
10 packets transmitted, 10 received, 0% packet loss, time 10100 ms
nsh> mqttc 192.168.20.1
mqttc is ready to begin publishing the time.
Press ENTER to publish the current time.
Press CTRL-D (or any other key) to exit.
mqttc published : "The time is 1970-01-01 00:00:57"
packet_id = 0x0000C96A,536916472
mqttc published : "The time is 1970-01-01 00:00:58"
packet_id = 0x000064B5,536916452
mqttc published : "The time is 1970-01-01 00:00:59"
packet_id = 0x0000865A,536916432
mqttc published : "The time is 1970-01-01 00:00:59"
packet_id = 0x0000432D,536916412
mqttc published : "The time is 1970-01-01 00:01:00"
packet_id = 0x00009596,536916392
mqttc published : "The time is 1970-01-01 00:01:00"
packet_id = 0x00004ACB,536916372
mqttc published : "The time is 1970-01-01 00:01:00"
packet_id = 0x00009165,536916352
mqttc published : "The time is 1970-01-01 00:01:00"
packet_id = 0x0000FCB2,536916332
mqttc published : "The time is 1970-01-01 00:01:00"
packet_id = 0x00007E59,536916312
mqttc disconnecting from 192.168.20.1
PC側の様子。
$ mosquitto_sub -t datetime The time is 1970-01-01 00:00:57 The time is 1970-01-01 00:00:58 The time is 1970-01-01 00:00:59 The time is 1970-01-01 00:00:59 The time is 1970-01-01 00:01:00 The time is 1970-01-01 00:01:00 The time is 1970-01-01 00:01:00 The time is 1970-01-01 00:01:00 The time is 1970-01-01 00:01:00
おまけ
$ git clone https://github.com/mickey-happygolucky/nuttx.git -b mqtt $ git clone https://github.com/mickey-happygolucky/apps.git -b mqtt $ cd nuttx $ tools/configure.sh -l configs/stm32f4discovery/rndis_mqtt $ make -j4 $ st-flash write nuttx.bin 0x8000000
