Page 50 of 195
AT.s LE Command Set v5.1.1b
Copyright © 2002-2021 BlueRadios, Inc.
200 S. Wilcox St., Unit 158 • Castle Rock, CO 80104 • USA • 303-957-1003 •
GATT Discovered Characteristic Descriptor (GATT_DCD)
GATT DISCOVER CHARACTERISTIC DESCRIPTOR EVENT
Function:
This event will be sent for each characteristic descriptor discovered by an ATGDCD
command.
Event Format:
GATT_DCD,<Conn_Handle>,<Char_Desc_Att_Handle>,<Char_Desc_UUID>
Event Values:
▪
Conn_Handle:
Connection handle
▪
Char_Desc_Att_Handle:
Characteristic descriptor attribute handle. [1-65535]
▪
Char_UUID:
UUID of the characteristic descriptor. [16-bit UUID = 4 chars]
Example(s):
1. ATGDCD is used to discover the characteristic descriptors of the BAS Battery Level
characteristic on a remote device. First, ATGDPSU is used to find the BAS service, which has a
start handle of 25 and an end handle of 28:
COMMAND:
ATGDPSU,0,180F
<cr>
RESPONSE:
<cr_lf>
OK
<cr_lf>
EVENT:
<cr_lf>
GATT_DPS,0,25,28,180F
<cr_lf>
EVENT:
<cr_lf>
GATT_DONE,0,0,0
<cr_lf>
Next, ATGDC is used to find the Battery Level characteristic:
COMMAND:
ATGDC,0,25,28
<cr>
RESPONSE:
<cr_lf>
OK
<cr_lf>
EVENT:
<cr_lf>
GATT_DC,0,27,12,2A19
<cr_lf>
EVENT:
<cr_lf>
GATT_DONE,0,2,0
<cr_lf>
Last, ATGDCD is used to find the Battery Level characteristic descriptors. The Start_Att_Handle
is set to 28, which is the Battery Level characteristic value 1 that was found by ATGDC.
The End_Att_Handle is also set to 19, since this is the last handle in the BAS service (thus the
last handle in the characteristic), which was found by ATGDPSU:
COMMAND:
ATGDCD,0,28,28
<cr>
RESPONSE:
<cr_lf>
OK
<cr_lf>
EVENT:
<cr_lf>
GATT_DCD,0,28,2902
<cr_lf>
EVENT:
<cr_lf>
GATT_DONE,0,3,0
<cr_lf>
