Serial At Command Mode - USR IOT Cortex-M7 Series At Command Manual

2.2.

Serial AT command mode

After the device is powered on and starts working, you can send commands through the serial port to set device parameters.
The syntax and usage of the AT command are described in details later.
The default parameters of the serial port are as follows: Baud rate 115200, None Parity bit, 8 Data bits, 1 Stop bit.
After the device is powered on and starts working, open the AT command debugging tool and set the serial port parameters.
Click 'open' and click '+++a'. The data window on the right receives 'a+ok'.AT this point, the device enters the command mode, and
AT command parameters can be set.
To enter the AT command mode, input characters '+++' and 'a' need to meet certain timing requirements, as shown below.
Timing sequence:
T1 > Serial port data packaging interval
T2 < 300ms
T3 < 300ms
T5 < 3s
To enter the command mode,the following procedure must be followed.
1. Start sending new packets,the device or tool send three continuous'+'to the USR module, and when the module receives'+++'
sequence, it replies with an 'a'
2. When the device or tool receives an 'a', it must send back an 'a' to the USR module within 3 seconds
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Enter Serial AT Command mode
Figure 4
Timing sequence diagram
Figure 5
6
AT command set
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