at.py Tool

[中文]

The at.py tool is used to modify various parameter configurations in the packaged 2 MB/4 MB AT production firmware (namely, factory_XXX.bin in the build/factory directory). These configurations include Wi-Fi configurations, certificate and key configurations, UART configurations, GATTS configurations, and more. When the default firmware does not meet your requirements, you can use the at.py tool to modify these parameter configurations in the firmware.

Detailed Steps

Please follow the detailed steps below to download the at.py tool, modify the configurations in the firmware, and flash the firmware. It is recommended to use a Linux system for development.

• Step 1: Install Python

• Step 2: Download at.py

• Step 3: Use at.py

• Step 4: Examples: Modify Firmware Configurations with at.py

• Step 5: Flash onto the Device

Step 1: Install Python

If you have already installed Python on your local machine, you can skip this step. Otherwise, please download and install Python according to the official Python documentation. It is recommended to use Python 3.8.0 or later versions.

After the installation is complete, you can open a command line and enter python --version to check the Python version.

Step 2: Download at.py

Visit the at.py webpage, click the “Download raw file” button to download the at.py file to your local machine.

Download at.py File

Step 3: Use at.py

Currently, at.py supports modifying parameter configurations in the firmware. To view the supported usage and instructions, enter python at.py modify_bin --help in the command line for more details.

Step 4: Examples: Modify Firmware Configurations with at.py

• Modify Wi-Fi Configuration

• Modify Certificate and Key Configuration

• Modify UART Configuration

• Modify GATTS Configuration

Note

• You can modify the parameter configurations of multiple functions at one go. For example, you can modify both Wi-Fi configuration and certificate and key configuration at the same time.

• The script does not check the validity of the modified parameter configurations. Please ensure that the input configurations are valid.

• The modified parameter configurations will have corresponding records in the mfg_nvs.csv file under the current mfg_nvs directory.

Modify Wi-Fi Configuration

The currently modifiable Wi-Fi parameter configurations are shown in the following table:

Parameter	Function	Description
--tx_power	Maximum transmission power of Wi-Fi	See ESP32-C2 Maximum transmission power for more details.
--country_code	Wi-Fi country code	See the cc field of Wi-Fi Country Code
--start_channel	Wi-Fi starting channel	See the schan field of Wi-Fi Country Code
--channel_number	Total number of Wi-Fi channels	See the nchan field of Wi-Fi Country Code

For example, you can use the following command to modify the maximum transmission power of Wi-Fi to 18 dBm, set the country code to US, starting channel to 1, and total channel number to 11:

python at.py modify_bin --tx_power 72 --country_code "US" --start_channel 1 --channel_number 11 --input factory_XXX.bin

• --tx_power 72: The unit is 0.25 dBm, and 72 represents 18 dBm.

• --input factory_XXX.bin: The input firmware file.

Modify Certificate and Key Configuration

The currently modifiable certificate and key configurations are shown in the following table:

Parameter	Function	Original File
--server_ca	CA certificate for TLS server	server_ca.crt
--server_cert	Certificate for TLS server	server_cert.crt
--server_key	Key for TLS server	server.key
--client_ca0	CA certificate for client 0	client_ca_00.crt
--client_cert0	Certificate for client 0	client_cert_00.crt
--client_key0	Key for client 0	client_key_00.key
--client_ca1	CA certificate for client 1	client_ca_01.crt
--client_cert1	Certificate for client 1	client_cert_01.crt
--client_key1	Key for client 1	client_key_01.key
--mqtt_ca	CA certificate for MQTT client	mqtt_ca.crt
--mqtt_cert	Certificate for MQTT client	mqtt_client.crt
--mqtt_key	Key for MQTT client	mqtt_client.key
--wpa2_ca	CA certificate for WPA2-Enterprise client	wpa2_ca.pem
--wpa2_cert	Certificate for WPA2-Enterprise client	wpa2_client.crt
--wpa2_key	Key for WPA2-Enterprise client	wpa2_client.key

For example, you can use the following command to modify the CA certificate, certificate, and key for the MQTT client:

python at.py modify_bin --mqtt_ca mqtt/mqtt_ca.crt --mqtt_cert mqtt/mqtt.crt --mqtt_key mqtt/mqtt.key --input factory_XXX.bin

• --input factory_XXX.bin: The input firmware file.

Modify UART Configuration

The modifiable UART configuration includes only the UART configuration for the AT command port. The configurable parameter configurations are shown in the following table:

Parameter	Function	Description
--uart_num	UART number for the AT command port	Only needs to be modified if the AT command port is also used as the AT log port. Ensure that the tx_pin and rx_pin below have the same pins as the AT log port. If the AT log port is only configured with the rx pin, you need to configure the following tx_pin to be consistent with the tx pin of the UART of the Download Firmware Port (please refer to Hardware Connection).
--baud	Baud rate of the AT command port	Original value: 115200
--tx_pin	TX pin of the AT command port	Please ensure that the set pin is not used by other functions.
--rx_pin	RX pin of the AT command port	Please ensure that the set pin is not used by other functions.
--cts_pin	CTS pin of the AT command port	Please ensure that the set pin is not used by other functions. If flow control is not used, set this parameter to -1.
--rts_pin	RTS pin of the AT command port	Please ensure that the set pin is not used by other functions. If flow control is not used, set this parameter to -1.

For example, you can use the following command to modify the baud rate to 921600, set the TX pin to GPIO17, the RX pin to GPIO16, and disable flow control for the AT command port:

python at.py modify_bin --baud 921600 --tx_pin 17 --rx_pin 16 --cts_pin -1 --rts_pin -1 --input factory_XXX.bin

• --input factory_XXX.bin: The input firmware file.

Modify GATTS Configuration

Before making modifications, please read the How to Customize Bluetooth® LE Services document to understand the meaning of each field in the GATTS configuration file gatts_data.csv .

The currently modifiable GATTS configurations are shown in the following table:

Parameter	Function
--gatts_cfg0	Update the row with index 0 in the gatts_data.csv file
--gatts_cfg1	Update the row with index 1 in the gatts_data.csv file
--gatts_cfg2	Update the row with index 2 in the gatts_data.csv file
--gatts_cfg3	Update the row with index 3 in the gatts_data.csv file
--gatts_cfg4	Update the row with index 4 in the gatts_data.csv file
--gatts_cfg5	Update the row with index 5 in the gatts_data.csv file
--gatts_cfg6	Update the row with index 6 in the gatts_data.csv file
--gatts_cfg7	Update the row with index 7 in the gatts_data.csv file
--gatts_cfg8	Update the row with index 8 in the gatts_data.csv file
--gatts_cfg9	Update the row with index 9 in the gatts_data.csv file
--gatts_cfg10	Update the row with index 10 in the gatts_data.csv file
--gatts_cfg11	Update the row with index 11 in the gatts_data.csv file
--gatts_cfg12	Update the row with index 12 in the gatts_data.csv file
--gatts_cfg13	Update the row with index 13 in the gatts_data.csv file
--gatts_cfg14	Update the row with index 14 in the gatts_data.csv file
--gatts_cfg15	Update the row with index 15 in the gatts_data.csv file
--gatts_cfg16	Update the row with index 16 in the gatts_data.csv file
--gatts_cfg17	Update the row with index 17 in the gatts_data.csv file
--gatts_cfg18	Update the row with index 18 in the gatts_data.csv file
--gatts_cfg19	Update the row with index 19 in the gatts_data.csv file
--gatts_cfg20	Update the row with index 20 in the gatts_data.csv file
--gatts_cfg21	Update the row with index 21 in the gatts_data.csv file
--gatts_cfg22	Update the row with index 22 in the gatts_data.csv file
--gatts_cfg23	Update the row with index 23 in the gatts_data.csv file
--gatts_cfg24	Update the row with index 24 in the gatts_data.csv file
--gatts_cfg25	Update the row with index 25 in the gatts_data.csv file
--gatts_cfg26	Update the row with index 26 in the gatts_data.csv file
--gatts_cfg27	Update the row with index 27 in the gatts_data.csv file
--gatts_cfg28	Update the row with index 28 in the gatts_data.csv file
--gatts_cfg29	Update the row with index 29 in the gatts_data.csv file
--gatts_cfg30	Update the row with index 30 in the gatts_data.csv file

For example, you can use the following command to modify the “perm” permission of the row with index 0:

python at.py modify_bin --gatts_cfg0 "0,16,0x2800,0x011,2,2,A002" --input factory_XXX.bin

• --input factory_XXX.bin: The input firmware file.

Step 5: Flash onto the Device

Attention

The AT firmware modified by at.py needs to be tested and verified for functionality based on your own product.

Please save the firmware before and after modification, and the download link, for possible issue debugging in the future.

Please follow the Flash firmware to complete it.

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