Template: Pico-ETH-CH9121 Guide

From Waveshare Wiki
Jump to: navigation, search


TCP Client

  • Connect the Pico-ETH-CH9121 (ETH module hereafter) to the router, and use the host PC as a TCP server. The PC should be connected to the same LAN as the ETH module
  • Use the SSCOM software, set the port to TCP server and you can check the local IP (the Target IP) and the port (Target port)
  • Run the NetModuleConfig.exe software on your PC
    1. Click the Search button to detect device
    2. Double-Click the device detected, then you can modify the network parameters in the left area
    3. After configuration, the ETH module will auto-restart, wait for a moment, search the device again and check the setting.
    4. Note that you need to modify the parameters according to the actual situation. The Mode should be TCP CLIENT, target IP and port is same as the TCP server.
  • After setting, you can listen to the data by the SSCOM software


  • Connect the Pico-ETH-CH9121 (ETH module hereafter) to the router, and use the host PC as a TCP CLIENT.
  • Run the NetModuleConfig.exe software on your PC
    1. Click the Search button to detect the ETH module
    2. Double-click the device detected
    3. Set the mode to TCP SERVER and modify other parameters according to the actual situation.
    4. Click the Set ALL button to save the setting
  • User the SSCOM software, configure as TCP CLIENT, and connect to the SERVER(The ETH module)


The UDP modes are the same as the TCP, the only difference is the mode is UDP CLIENT/SERVER but not the TCP CLIENT/SERVER.

Using with Pico

Hardware connection

ETH Pico Description
5V VSYS Power input
GND GND Ground
RXD1 GP0 UART 1 data input
TXD1 GP1 UART 1 data output
RXD2 GP4 UART 2 data input
TXD2 GP5 UART 2 data output
CFG0 GP14 Network configrate enable pin
RST1 GP17 Reset pin

=Configurate Environment

To use the Pico, you need to configure your PC or the Raspberry Pi first.
Please refer to the official guide about the setting Pico Manual


We use Raspberry Pi board as examples

Download examples

Open the terminal and run the following commands:

sudo apt-get install p7zip-full
cd ~
sudo wget  https://www.waveshare.com/w/upload/a/a4/Pico_ETH_CH9121_CODE.7z
7z x Pico_ETH_CH9121_CODE.7z -o./Pico_ETH_CH9121_CODE
cd ~/Pico_ETH_CH9121_CODE
cd Pico/c/build/

C examples

  • Go intot the c directory
cd ~/Pico_ETH_CH9121_CODE/Pico/C/
You can use the Pico_ETH_CH9121_CODE/Pico/C/Serial Port Parameter Configuration: configura module
Pico_ETH_CH9121_CODE/Pico/C/RX_TX: Echo examples, receive data and echo
  • Go into examples directory and export sdk
cd build
export PICO_SDK_PATH=../../pico-sdk
You need to modify the path to the actual one if you use directly path
  • Generate the Makefile file
cmake ..
  • Build the examples
make -j9
  • After building, copy the .uf2 file to the Pico
Press the BOOTSEL button of Pico and hold it, connect the pico to your Pi by micro USB cable and then release the button. The portable disk RPI-RP2 is recognized, you need to copy the uf2 file to the portable disk.
cp main.uf2 /media/pi/RPI-RP2/

=Python examples

  • Press and hold the BOOTSEL button of pico, connect it to Raspberry Pi or PC by micro USB cable, and then release the button
  • The Pico is recognized as portable disk RPI-RP2, copy the rp2-pico-20210418-v1.15.uf2 file to the portable disk
  • Open the Thonny IDE
  • Choose Tools -> Options .. -> Interpreter
  • Choose MicroPython(Raspberry Pi Pico) and the related port.
  • If your Thonny IDE doesn't support Pico, you need to update it to the newest version
sudo apt upgrade thonny
  • Click File -> Open... -> python/RX_TX.py to run the codes.

Codes Description

C codes
  • Data types:
#define UCHAR unsigned char
#define UBYTE uint8_t
#define UWORD uint16_t
#define UDOUBLE uint32_t
  • Initailize module:
void CH9121_init(void);
  • Parameters for configuring modules
UCHAR CH9121_Mode           //Mode
UCHAR CH9121_LOCAL_IP[4]    //Device IP
UCHAR CH9121_GATEWAY[4]     //Gateway
UCHAR CH9121_SUBNET_MASK[4] //Subnet mask
UCHAR CH9121_TARGET_IP[4]   //Target IP
UWORD CH9121_PORT1          //Device port
UWORD CH9121_TARGET_PORT    //Target port
UDOUBLE CH9121_BAUD_RATE    //baud rate of serial 
  • You can configure the module by the following functions with serial commands
void CH9121_TX_4_bytes(UCHAR data, int command); //Can be used to configure the mode, random port, disconnect network, clear buffer, DHCP, UART2
void CH9121_TX_5_bytes(UWORD data, int command);//Can be used to set the port of Serial
void CH9121_TX_7_bytes(UCHAR data[], int command);//Can be used to set IP, subnet mask, gateway.
void CH9121_TX_BAUD(UDOUBLE data, int command);//Can be used to set the baud rate of Serial.
void CH9121_Eed(); // Can be used to save setting to EEPROM, enable the setting, reset module, exit from setting mode

You just need to modify the Serial Port Parameter Configuration.py for setting the module

ODE = 1  #0:TCP Server 1:TCP Client 2:UDP Server 3:UDP Client
GATEWAY = (169, 254, 88, 1)   # GATEWAY
TARGET_IP = (169, 254, 88, 17)# TARGET_IP
LOCAL_IP = (169,254,88,70)    # LOCAL_IP
SUBNET_MASK = (255,255,255,0) # SUBNET_MASK
LOCAL_PORT1 = 5000             # LOCAL_PORT1
LOCAL_PORT2 = 4000             # LOCAL_PORT2
TARGET_PORT = 3000            # TARGET_PORT
BAUD_RATE = 115200            # BAUD_RATE