Data Sheet

GPS Module
L80 GPS Protocol Specification
L80_GPS_Protocol_Specification Confidential / Released 18 / 41
3.3. Packet Type: 001 PMTK_ACK
Acknowledgement of PMTK command. In order to inform the sender whether the receiver has received
the packet, an acknowledge packet PMTK_ACK should return after the receiver receives a packet.
Some commands will cause the GPS module to restart or change the baud rate.There is no PMTK_ACK
for those commands as listed below.
PMTK_CMD_HOT_START
PMTK_CMD_WARM_START
PMTK_CMD_COLD_START
PMTK_CMD_FULL_COLD_START
PMTK_SET_NMEA_BAUDRATE
Example:
$PMTK001, 869,3*37<CR><LF>
Field
Description
$
Each NMEA message starts with ‘$’
PMTK
MTK proprietary message
Packet type
001
Command
The packet type that the acknowledge responds
Flag
‘0’ = Invalid packet
‘1’ = Unsupported packet type
‘2’ = Valid packet, but action failed
‘3’ = Valid packet, action succeeded
*
End character of data field
Checksum
Hexadecimal checksum
<CR><LF>
Each of message
3.4. Packet Type: 101 PMTK_CMD_HOT_START
This message is used to hot start the GPS module (use all available data in the NV store). Normally hot
start means the GPS module was powered down less than 3 hours (RTC must be alive) and its ephemeris
is still valid. As there is no need for downloading ephemeris, it’s the fastest startup method.
Quectel
Confidential