Specifications

HM-BT4502 V1.0
13/ 43 www.hoperf.com
package interval greater than 20ms.
9 Serial Port AT Instructions
The string beginning with "TTM" is parsed and executed as an AT instruction
and returned the execution result "TTM: OK\r\n\0" or "TTM: ERP\r\n\0", etc.
The serial data package that does not start with "TTM" will be considered as
the pass-through data.
9.1 Set the Connection Interval
Input the string "TTM: CIT-X ms" to the serial port RX to set BLE connection
interval, where X= "20", "30", "50", "100", "200", "300", "400", "500", "1000",
"1500", "2000". The unit is ms (the above data format is ASCII code). For
example, "TTM: CIT-30ms" means setting the connection interval to 30ms.
After executing this instruction, the following confirmation will be obtained from
serial TX:
"TTM: TIMEOUT\r\n\0"means that the change timed out and failed.
"TTM: OK\r\n\0" means that the change is successful and the program is
running at a new connection interval.
The success of this connection interval setting depends on the limitation of the
mobile device on the interval, and the maximum connection interval varies
from the mobile phone system version.