Network example using pyserial and esp8266 AT firmware.
You don't need Ethernet card.
You need only pyserial library and ESP8266 module.
I recently bought a LuxkFox Pico Mini board.
It's a very small Linux board.
buildroot linux works.
But there is no network.
So, I made it to use the network with this board.
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Linux board with UART functionality
As long as pyserial works, distribution doesn't matter. -
ESP8266 module like ESP01
ESP8266 has SoCs with 1MB Flash (like ESP01) and 4MB Flash (like ESP12), it doesn't matter. -
Regulator that can convert 5V to 3.3V
I used AMS1117 breakout.
This breakout is equipped with a capacitor, so no other components are required.
-
UART-USB converter
Used for initial firmware settings.
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pyserial library
In your buildroot environment you can enable it with this.
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ESP8266 AT Firmware
AT firmware version can be identified by AT version and SDK version.
AT version V2 added MQTT and HTTP commands.
However, AT version V2 does not support 1M SoCs like ESP01.
When using 1M SoCs like ESP01, it is necessary to use AT version V1.
This repository works with both V1 and V2.
You can download AT version V1 from here.
Note
Some firmware here does not support 1M SoC such as ESP01.
I used this.
AT+GMR
AT version:1.7.5.0(Oct 20 2021 19:14:04)
SDK version:3.0.5(b29dcd3)
compile time:Oct 20 2021 20:13:50
Bin version(Wroom 02):1.7.5
- Terminal software such as CoolTerm
I use TeraTrem.
You can down load from here.
The 3.3V output of the UART-USB converter has too little current to be used.
Power is supplied using 5V from the UART-USB converter and 3.3V from the regulator.
- GPIO2 must be pulled up.
- GPIO0 must be connected to GND.
- CH_PD must be pulled up.
- RESET must be pulled up.
Click here for details.
- GPIO2 must be pulled up.
- GPIO0 must be pulled up.
- CH_PD must be pulled up.
- RESET must be pulled up.
Connect to ESP01 at 115200 bps using terminal software.
AT+GMR
AT version:1.6.2.0(Apr 13 2018 11:10:59)
SDK version:2.2.1(6ab97e9)
compile time:Jun 7 2018 19:34:26
Bin version(Wroom 02):1.6.2
OK
AT+CWMODE=1
OK
AT+CWLAP
+CWLAP:(3,"Picking",-86,"34:12:98:08:4b:4a",1,-4)
+CWLAP:(4,"ctc-g-fa4a2e",-92,"c0:25:a2:b1:8c:2e",2,3)
+CWLAP:(4,"aterm-e625c0-g",-49,"c0:25:a2:ac:cb:ba",3,15)
+CWLAP:(1,"aterm-e625c0-gw",-48,"c2:25:a2:ac:cb:ba",3,15)
OK
AT+CWJAP="Your AP's SSID","Your AP's password"
WIFI CONNECTED
WIFI GOT IP
OK
AT+CIPSTA?
+CIPSTA:ip:"192.168.10.142"
+CIPSTA:gateway:"192.168.10.1"
+CIPSTA:netmask:"255.255.255.0"
OK
AT+CWQAP
OK
AT firmware has a function that automatically connects to the last connected AP when the module is reset.
Using this function, you can omit the SSID and password.
AT+RST
WIFI CONNECTED
WIFI GOT IP
AT+CIPSTA?
+CIPSTA:ip:"192.168.10.142"
+CIPSTA:gateway:"192.168.10.1"
+CIPSTA:netmask:"255.255.255.0"
OK
If you want to change the AP, execute the following command again.
AT+CWJAP="New AP's SSID","New AP's password"
WIFI CONNECTED
WIFI GOT IP
1.Make sure TE(terminal equipment) is in sta mode
AT+CWMODE=1
OK
2.Make sure TE got ip address
AT+CIPSTA?
+CIPSTA:ip:"192.168.10.115"
+CIPSTA:gateway:"192.168.10.1"
+CIPSTA:netmask:"255.255.255.0"
OK
3.Let's update
AT+CIUPDATE
+CIPUPDATE:1 found server
+CIPUPDATE:2 connect server
+CIPUPDATE:3 got edition
+CIPUPDATE:4 start start
OK
4.Check firmware version
AT+GMR
AT version:1.7.5.0(Oct 20 2021 19:14:04)
SDK version:3.0.5(b29dcd3)
compile time:Oct 20 2021 20:13:50
Bin version(Wroom 02):1.7.5
OK
- ESP01(Tx) - UART-RX port of host
- ESP01(Rx) - UART-TX port of host
- ESP01(Gnd) - Gnd of host
- ESP01(3v3) - 3V3 of host(*1)
(*1) It is necessary to be able to supply sufficient current.
ls /dev/tty*
/dev/tty /dev/ttyFIQ0 /dev/ttyS3 /dev/ttyS4
You can use /dev/ttyS3 and /dev/ttyS4.
/dev/ttyS3 is IO56(TX)/IO57(RX).
/dev/ttyS4 is IO53(TX)/IO52(RX).
In environments where networking is supported, use git to retrieve the files.
git clone https://github.com/nopnop2002/python-esp8266
In environments where networking is not supported, use RNDIS to retrieve the files.
Ubuntu 20.04/Debian 11 is required as the RNDIS server.
In the Ubuntu 22.04/Debian 12 environment, the usb0 interface has been changed to a "consistent network device naming method".
Clone to RNDIS server.
git clone https://github.com/nopnop2002/python-esp8266
When power is supplied to the RNDIS client from the Ubuntu/Dibian machine, the USB0 interface will be displayed on the Ubuntu/Debian side as shown below.
$ sudo ifconfig usb0
usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::a742:1ab5:c616:d016 prefixlen 64 scopeid 0x20<link>
ether 7a:da:62:7c:d5:bb txqueuelen 1000 (Ethernet)
RX packets 21 bytes 2169 (2.1 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 39 bytes 8001 (8.0 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
$ nmcli conn show
NAME UUID TYPE DEVICE
Wired connection 2 ea035181-2f58-3f41-bf2b-89c5022bb4e0 ethernet usb0
Wired connection 1 5bfff474-56e9-3a46-81d7-3b3a7d5692d7 ethernet enp4s0
Assign a fixed IP address to usb0 interface using the nmcli command.
The fixed IP address assigned to the Ubuntu/Debian side can be any as long as it is on the same segment as the RNDIS client board.
$ sudo nmcli connection down "Wired connection 2"
$ sudo nmcli connection modify "Wired connection 2" ipv4.addresses "172.32.0.100/16"
$ sudo nmcli connection modify "Wired connection 2" ipv4.method manual
$ sudo nmcli connection up "Wired connection 2"
$ nmcli device show usb0
GENERAL.DEVICE: usb0
GENERAL.TYPE: ethernet
GENERAL.HWADDR: DA:1F:7F:84:10:69
GENERAL.MTU: 1500
GENERAL.STATE: 100 (connected)
GENERAL.CONNECTION: Wired connection 2
GENERAL.CON-PATH: /org/freedesktop/NetworkManager/ActiveConnection/6
WIRED-PROPERTIES.CARRIER: ƒIƒ“
IP4.ADDRESS[1]: 172.32.0.100/16
IP4.GATEWAY: --
IP4.ROUTE[1]: dst = 172.32.0.0/16, nh = 0.0.0.0, mt = 101
IP6.ADDRESS[1]: fe80::f220:3c47:db11:8fbe/64
IP6.GATEWAY: --
IP6.ROUTE[1]: dst = fe80::/64, nh = ::, mt = 101
Check the result with ifconfig.
$ sudo ifconfig usb0
usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.32.0.100 netmask 255.255.0.0 broadcast 172.32.255.255
inet6 fe80::f220:3c47:db11:8fbe prefixlen 64 scopeid 0x20<link>
ether da:1f:7f:84:10:69 txqueuelen 1000 (Ethernet)
RX packets 53 bytes 7107 (7.1 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 109 bytes 19284 (19.2 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Now you can ping the RNDIS client and use ssh and scp.
$ ping 173.32.0.93
PING 173.32.0.93 (192.168.10.45) 56(84) bytes of data.
64 bytes from 192.168.10.45: icmp_seq=1 ttl=64 time=0.607 ms
64 bytes from 192.168.10.45: icmp_seq=2 ttl=64 time=0.365 ms
64 bytes from 192.168.10.45: icmp_seq=3 ttl=64 time=0.268 ms
64 bytes from 192.168.10.45: icmp_seq=4 ttl=64 time=0.373 ms
^C
--- 173.32.0.93 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3059ms
rtt min/avg/max/mdev = 0.268/0.403/0.607/0.124 ms
$ scp -r python-esp8266 root@172.32.0.93:/root
root@172.32.0.93's password:
cd python-esp8266/connectWiFi
# Root privileges are required on Ubuntu/Debian
sudo -E python3 main.py --device /dev/ttyS3
device=/dev/ttyS3
speed=115200
debug=False
ip=['192.168.10.108', '192.168.10.1', '192.168.10.1']
mac=5c:cf:7f:6b:00:1b
cd python-esp8266/connectWiFi
# buildroot does not require root privileges
python3 main.py --device /dev/ttyS3
device=/dev/ttyS3
speed=115200
debug=False
ip=['192.168.10.108', '192.168.10.1', '192.168.10.1']
mac=5c:cf:7f:6b:00:1b
We can get a module for UART communication.
We can write AT firmware to this.
It has a 5V->3.3V regulator and can supply power directly from 5V.
Although it supplies 5V power, the TTL level of UART is 3.3V.
Only $1 for AliExpress/eBay.
External pin header is 5V,GND,TXD,RXD.
It has a 5V->3.3V regulator and can supply power directly from 5V.
Although it supplies 5V power, the TTL level of UART is 3.3V.
