Specifications

35
Ex) NOTIFY – First message to HOST when power is applied: READY⤶
Command
READY
command set
R
E
A
D
Y
\r
ascii set
0x52
0x45
0x41
0x44
0x59
0x0D
Ex) RESPONSE – Request failed (BAD_HOST_COMMAND) : ERROR⤶
Command
ERROR
Command set
E
R
R
O
R
\r
ascii set
0x45
0x52
0x52
0x4F
0x52
0x0D
Basic protocol operation
BT transmits the corresponding RESPONSE after receiving a request from HOST. HOST may
basically expect a RESPONSE of “OK⤶” or “ERROR⤶”, and may receive a specific RESPONSE
corresponding to the request.
Description of BT GPIO
Separate GPIO is allocated to notify BT status information or control specific BT functions in
HOST.
GPIO
Name
Direction
I/O
Description
GPIO 15
Power
State LED
Output
Low
BT Power Off
High
BT Power On
GPIO 36
Connected
State LED
Output
Low
BT Device Disconnected
High
BT Device Connected
GPIO 24
BT Command
Port
Input
Low
AT Command Mode
High
Bypass Mode
GPIO 34
BT Command
State LED
Output
Low
Bypass Mode State
High
AT Command Mode State
- BT switches to Bypass Mode when it is connected (AT Command mode can be switched to GPIO24)
- BT switches to AT Command Mode when disconnected (Bypass mode cannot be switched to GPIO24)
- To change from Bypass to AT Command in connected state, change GPIO24 from HIGH to LOW.
- To change from AT Command to Bypass in connected state, change GPIO24 from LOW to HIGH.