LG290P unable to get NMEA output from UART2

Other
1

Hello. I’ve two SparkFun Quadband GNSS RTK Breakout - LG290P (Qwiic) boards.
I’m working on a project requiring both RTCM and GNRMC (NMEA) output on UART2.
The boards have been configured as base station and I enabled RTCM and NMEA on both UART1 (USB) and UART2 ($PQTMCFGPROT,W,1,1,00000005,00000005* and $PQTMCFGPROT,W,1,2,00000005,00000005*).
On UART1 everything is behaving as expected… I get all RTCM and NMEA messages which I enabled. On UART2 instead I only get the RTCM stuff. No way to get GNRMC on UART2 even if the NMEA enable on UART2 has been acknowledged:

$PQTMCFGPROT,W,1,2,00000005,000000053B
$PQTMCFGPROT,OK6B

$PQTMCFGPROT,R,1,23E
$PQTMCFGPROT,OK,1,2,00000005,0000000568

Any idea about what could the problem be and how to solve it ?

The board has been updated to Quectel_LG290P_Firmware_Release_V0105S.zip but it was behaving in the same manner also with V03
Thanks, Joel

2

Hi Joel (@Joel_Brenner ),

I don’t know if this will help, or not. But version 5 of the LG290P firmware allows message rates to be set independently across the three ports. To set the GGA rate to 1 on UART2, try:

$PQTMCFGMSGRATE,W,1,2,GGA,1*09

image

I hope this helps,
Paul

3

Alleluia !!! yes this fixed the problem…
Many thanks

4

still some strange behavior after firmware update MSM6 for Beidou is output with twice the frequency of the other constellation MSM6:

On a very simple console application I’m parsing the UART2 serial traffic and I collect some statistics.

RTCM message statistichs:
RTCM-1076: NrMsg = 13; Total size [Byte]= 2639; Max size [Byte]= 203
RTCM-1086: NrMsg = 13; Total size [Byte]= 1716; Max size [Byte]= 132
RTCM-1096: NrMsg = 13; Total size [Byte]= 3562; Max size [Byte]= 274
RTCM-1126: NrMsg = 26; Total size [Byte]= 6253; Max size [Byte]= 366
RTCM-1136: NrMsg = 13; Total size [Byte]= 637; Max size [Byte]= 49

NMEA mess: 13
Got GNRMC Week: 2374 TOW: 475055

The console application was reporting the same number of MSM6 messages for all constellations before the firmware update.

According to your post I used the following commands to control the MSM6 rate (1-Hz rate):

$PQTMCFGMSGRATE,W,1,2,RTCM3-107X,1,0*2C 
$PQTMCFGMSGRATE,W,1,2,RTCM3-109X,1,0*22 
$PQTMCFGMSGRATE,W,1,2,RTCM3-111X,1,0*2B 
$PQTMCFGMSGRATE,W,1,2,RTCM3-112X,1,0*28 
$PQTMCFGMSGRATE,W,1,2,RTCM3-113X,1,0*29

Are these correct (according to the doc and considering your update on v0105 PQTMCFGMSGRATE )?

Now it seems that $PQTMCFGMSGRATE,W,1,2,RTCM3-107X,1,0*2C isn’t supported I simply get no answer for this message. Using the old message structure:
$PQTMCFGMSGRATE,W,RTCM3-107X,1,0*2F I get acknowledged.

Messages 109X, 111X,112X and 113X are positively acknowledged also with the new message structure (but not GPS)… is this a bug in the firmware ?

$PQTMCFGMSGRATE,R,1,2,RTCM3-112X*2C
Tells me:
$PQTMCFGMSGRATE,OK,1,2,RTCM3-112X,1,0*7B
so RTCM-1126 on UART2 should be 1-Hz but I get 2Hz..

Any idea about what’s going on ? or what I’m doing wrongly ?

If I enable RTCM on UART1 and I switch to MSM7 I can use QGNSS V2.0 application to monitor the RTCM messages (not orking for MSM6)

image
image752×571 49.6 KB

As you can se there are always 2 1027 messages per epoch, a big followed by a small one. I did not inspected the content of these messages … is LG290P splitting the MSM measurements over 2 1027 messages because there is a size limitation and both 1027 messages are referring to the same measurement epoch ?

Joel

5

Hi Joel,

I don’t know the full answer to this, but, yes, RTCM messages are limited to 1KByte. The GNSS will split the data across multiple messages if it needs to.

Best,
Paul