Micro Tracker Reference Guide FW 1.7 V1.1
Page 25 of 39
11th october 2018
Restricted distribution
5.1.2
Confirmed uplink
The device can be configured to request LoRa confirmation for a collection of uplink message types. The
parameter
confirmed_ul_bitmap
is used to select the message types that requires a confirmation. Only
message types in the range 0x00 to 0x0F can be selected.
Example:
Confirmed uplink of message types 0x0 and 0x3:
bitmap = 2
0
+ 2
3
= 1 + 8 = 9.
The parameter
confirmed_ul_retry
gives the number of retransmissions that the tracker should do in the case
where the LoRa confirmation is not received.
A value 0 means that the uplink will request the LoRa confirmation but will not retry in a case of a failure.
5.2
Encoded form
Some parameters are encoded with the following algorithms:
static float _step_size (float
lo
, float
hi
, unsigned
nbits
, unsigned
nresv
)
{ return 1.0/((((1 <<
nbits
) -1) -
nresv
)/(
hi
-
lo
)); }
float mt_value_decode(uint32_t
value
, float
lo
, float
hi
, unsigned
nbits
, unsigned
nresv
)
{ return ((value -
nresv
/2) * _step_size(
lo
,
hi
,
nbits
,
nresv
) +
lo
);}
Where:
✓
nbits:
number of bits used to encode.:
✓
lo:
min value that can be encoded
✓
hi:
max value that can be encoded
✓
nresv
: number of reserved values, not used for the encoding.
5.3
Common message header
Common header
Data
Byte 0
Byte 1
Byte 2
Byte 3
Byte 4
Variable
Type
Status
Battery
Temperature
Ack/opt
Information
Type:
refer to
Message types
Status:
Bit7-5
Operating mode:
➢
0- Standby
➢
1- Motion tracking
➢
2- Permanent tracking
➢
3- Motion start/end tracking
➢
4- Activity tracking
➢
5- OFF
Bit 4
Set if the user alert/SOS has been entered
Bit 3
Set if the tracker is in tracking state, else idle state.
Bit 2
Set if the tracker is moving
Bit 1
Set for a periodic position message
Bit 0
Set for a position on demand message