ATC and MQTT environment settings can be changed in the PXM environment file (pxm.ini) in the P4M-440G's file system.
| PXM | Parameter | Description | Default | Values |
|---|---|---|---|---|
| ATC | atc_uart_dev | UART Device ID | "uart0" | "uart0","uart1" |
| ATC | atc_uart_baud | UART Baudrate (bps) | 19200 | 1200 ~ 115200 |
| ATC | atc_uart_opt | UART Option | "n81n" | "n81n"(fixed) - n: No parity - 8: 8 data bits - 1: 1 stop bit - n: No flow-control |
| ATC | atc_cmd_buf_size | Command Buffer Size (Byte) | 256 | 128 ~ 2048 |
| MQTT | mqtt_max_topic_len | Max. Topic Buffer Size (Byte) | 128 | 64 ~ 1024 |
| MQTT | mqtt_max_msg_len | Max. Message Buffer Size (Byte) | 256 | 64 ~ 4096 |
| MQTT | mqtt_max_pub_buf | MQTT PUBLISH Topic Buffer Quantity | 4 | 4 ~ 32 |
| MQTT | mqtt_max_sub_buf | MQTT SUBSCRIBE Topic Buffer Quantity | 4 | 4 ~ 32 |
※ Due to limited memory capacity, MQTT buffer-related settings may not be usable even within the specified range depending on the settings of other items. It is recommended to use default values, so please only change them if absolutely necessary, and make sure to conduct sufficient testing after the changes.
Changing the UART baudrate to 9600 bps
| pxm.ini (original) | pxm.ini (modified) |
|---|---|
| atc_uart_baud=19200 | atc_uart_baud=9600 |
Changing the maximum MQTT topic buffer size to 256 bytes
| pxm.ini (original) | pxm.ini (modified) |
|---|---|
| mqtt_max_topic_len=128 | mqtt_max_topic_len=256 |
If you modify or delete files stored in the P4M-440G's file system, MQTT functionality may not work correctly. In such cases, you should use PHPoC Debugger to re-upload the ATC/MQTT package to the P4M-440G's file system. You can download the ATC/MQTT package from the online repository.