User's Manual

Enhanced Class 1 Bluetooth v2.1 Module
User’s Guide
Americas: [phone] Option 2
Europe: [phone]
Hong Kong: [phone]
www.lairdtech.com/wireless
160
CONN-GUIDE-BT740_v0.2
The NU object is defined with the following attributes:
Attribute Tag
Data Type
Comments
MDC_ATTR_ID_HANDLE
2337
HANDLE
Always: 1
MDC_ATTR_ID_TYPE
2351
TYPE
Const
MDC_ATTR_METRIC_SPEC_SMAL
L
2630
METRIC_SPEC_SMALL
Const
MDC_ATTR_UNIT_CODE
2454
OID_TYPE
Var:Weight
Units
MDC_ATTR_ATTRIBUTE_VAL_MA
P
2645
ATTR_VAL_MAP
2646,2448
MDC_ATTR_TIME_STAMP_ABS
2448
ABSOLUTE_TIME
Var:Time
MDC_ATTR_NU_VAL_OBS_SIMP
2646
SIMPLE_NU_OBS_VAL
Var:Weight
MDC_ATTR_NU_ACCUR_MSMT
2378
FLOAT_TYPE
Always: 1
MDC_ATTR_MSMT_STAT
2375
MEASUREMENT_STATU
S
Var:Meas.
Stat.
The attributes commented as ‘variables’ expose to the host for reading and writing via the UART interface
using AT+HAG and AT+HAS commands respectively and are described in detail elsewhere in this
document.
The UART interface identifies the variable attributes mentioned above using an attribute ID and an
additional sub ID. The concept of ‘sub ID’ is a Laird artefact and is not part of any IEEE standard, but the
attribute ID is the same as those defined in the IEEE standard in most cases. The complete list for the
Weigh Scale specialization is as per the table below and should be used with the agent attribute
read/write commands AT+HAG and AT+HAS.
Note: The attribute values passed back and forth from the host are NOT validated in any way by the
firmware in the Laird module. It is up to the host to ensure that the correct data writes into an
attribute. Any illegal values are picked up at time of Continua Alliance certification testing which
prevents certification.
Table 14-1: Variable Attributes in Weigh Scale Specialization
Attribute Name (See IEEE spec for
format)
Attr ID
Sub ID
Size in bytes
Weight
2646
0
4
Weight Units
2454
0
2
Time
2448
0
8
Power Status
2389
0
2
Battery Charge
2460
0
2
Time Battery Remain – value
2440
0
4
Time Battery Remain – unit
2440
1
2
Measurement Status
2375
0
2