Does #define NMEA_EXT WIRED_NMEA disable output of GGA sentences?

[j-lang]

I assumed that with a attached Bluetooth adapter all NMEA sentences are sent to the wired serial interface with the setting:
#define NMEA_EXT WIRED_NMEA
in BoardConfig.h.
What I noticed is, that no GGA sentences are sent to Micronet and wired serial interface when I set this configuration parameter. On a via Bluetooth connected smartphone, the interface log shows only RMC and VTG sentences, but no other. The Micronet display shows time and date, COG, SOG but LON/LAT.
After changing back to
#define NMEA_EXT USB_NMEA
LON/LAT are shown immediately.
Is there a limitation for the limited Bluetooth bit rate of 9600 or do I misinterpret the documentation for NMEA_EXT setting?

[Rodemfr]

Changing NMEA_EXT to WIRED_NMEA should not change the way GGA sentences are handled by MTN, in theory.
If I understand well, you receive GGA sentences from NMEA_EXT (so WIRED_NMEA pins when the problem occurs), and MTN sends LAT:LON to you Micronet devices. Correct ?
Another question : who is sending GGA to MTN, a M8N GPS, OpenCPN, something else ?

[j-lang]

I have a M8N GPS receiver connected to the Micronet interface that sends GGA, RMC and VTG to micronet devices, also to usb serial.
If I change from WIRED_NMEA to NMEA_EXT, there is only RMC and VTG on serial and micronet devices.

[Rodemfr]

It looks like a bug. I will first solve the reset loop issue and then try to reproduce this one.

[Rodemfr]

I made a quick test with my setup and it works fine. I suspect a unconsistent BoardConfig.h. NMEA config is not very user friendly. Can you post your BoardConfig.h ?

[j-lang]

/***************************************************************************
 *                                                                         *
 * Project:  MicronetToNMEA                                                *
 * Purpose:  Decode data from Micronet devices send it on an NMEA network  *
 * Author:   Ronan Demoment                                                *
 *                                                                         *
 ***************************************************************************
 *   Copyright (C) 2021 by Ronan Demoment                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************
 */

#ifndef BOARDCONFIG_H_
#define BOARDCONFIG_H_

/***************************************************************************/
/*                              Includes                                   */
/***************************************************************************/

/***************************************************************************/
/*                              Constants                                  */
/***************************************************************************/

// Select EU (868MHz) or not-EU (915MHz) Micronet frequency
// 0 -> EU (868Mhz)
// 1 -> non-EU (915Mhz)
#define FREQUENCY_SYSTEM 0

// Selects on which I2C bus is connected compass as per Wiring library definition
#if defined(ARDUINO_TEENSY35) || defined(ARDUINO_TEENSY36)
#define NAVCOMPASS_I2C Wire1 // SDA1: 38 SCL1: 37
#else                        // Teensy 4.0 Configuration
#define NAVCOMPASS_I2C Wire  // SDA0: 18 SCL0: 19
#endif

// CC1101/SPI pins
#if defined(ARDUINO_TEENSY35) || defined(ARDUINO_TEENSY36)
#define CS0_PIN  10
#define MOSI_PIN 11
#define MISO_PIN 12
#define SCK_PIN  14
#define GDO0_PIN 24
#else // Teensy 4.0 Configuration
#define CS0_PIN  10
#define MOSI_PIN 11
#define MISO_PIN 12
#define SCK_PIN  13
#define GDO0_PIN 14
#endif

// NMEA GNSS UART pins
#if defined(ARDUINO_TEENSY35) || defined(ARDUINO_TEENSY36)
#define GNSS_UBLOXM8N 1 // Set to one if your GNSS is a UBLOX M8N, 0 else. If set to one, GNSS will be automatically configured at startup
#define GNSS_SERIAL   Serial1
#define GNSS_BAUDRATE 9600
#define GNSS_RX_PIN   0
#define GNSS_TX_PIN   1
#else                   // Teensy 4.0 Configuration
#define GNSS_UBLOXM8N 1 // Set to one if your GNSS is a UBLOX M8N, 0 else. If set to one, GNSS will be automatically configured at startup
#define GNSS_SERIAL   Serial1
#define GNSS_BAUDRATE 9600
#define GNSS_RX_PIN   0
#define GNSS_TX_PIN   1
#endif

// USB UART params
#define USB_NMEA     SerialUSB
#define USB_BAUDRATE 115200

// Wired UART params
#if defined(ARDUINO_TEENSY35) || defined(ARDUINO_TEENSY36)
#define WIRED_NMEA     Serial5
#define WIRED_BAUDRATE 115200
#define WIRED_RX_PIN   34
#define WIRED_TX_PIN   33
#else // Teensy 4.0 Configuration
#define WIRED_NMEA     Serial2
#define WIRED_BAUDRATE 9600
#define WIRED_RX_PIN   7
#define WIRED_TX_PIN   8
#endif

// The console to use for menu and NMEA output
// USB_NMEA -> USB-Serial link
// WIRED_NMEA -> Teensy's physical UART
#define CONSOLE  USB_NMEA
#define NMEA_EXT USB_NMEA

// Defines which data comes from which link
// LINK_NMEA_EXT -> data comes from external NMEA link (WIRED_NMEA)
// LINK_NMEA_GNSS -> data comes from GNSS NMEA link (GNSS_SERIAL)
// LINK_MICRONET -> data comes from Micronet network
// LINK_COMPASS -> data comes from LSM303 (NAVCOMPASS_I2C)
#define NAV_SOURCE_LINK     LINK_NMEA_EXT  // Navigation data (RMB)
#define GNSS_SOURCE_LINK    LINK_NMEA_GNSS // Positionning data (RMC, GGA, VTG)
#define WIND_SOURCE_LINK    LINK_MICRONET  // Wind data (MWV)
#define DEPTH_SOURCE_LINK   LINK_MICRONET  // Depth data (DPT)
#define SPEED_SOURCE_LINK   LINK_MICRONET  // Speed data (VHW, VLW)
#define VOLTAGE_SOURCE_LINK LINK_MICRONET  // Battery voltage data (XDR)
#define SEATEMP_SOURCE_LINK LINK_MICRONET  // Temperature data (MTW)
#define COMPASS_SOURCE_LINK LINK_COMPASS   // Heading data (HDG)

// Navigation softwares can send a wrong RMB sentence and invert "FROM" and "TO" fields
// If you see your Micronet display showing the "FROM" waypoint name instead of the "TO"
// on the DTW & BTW pages, then change the following configuration switch to 1
#define INVERTED_RMB_WORKAROUND 0

// In case your displays would have difficulties to receive data from the Tacktick wind
// transducer because of a poor signal/noise ratio, you can ask MicronetToNMEA to repeat
// the values of AWA & AWS on the network by setting MICRONET_WIND_REPEATER to 1. Set it
// to 0 else.
#define MICRONET_WIND_REPEATER 0

// In case your Micronet system would not have SPD data (speed on water), you can set this
// compile switch to 1 to ask MicronetToNMEA to emulate SPD with SOG value from GNSS.
// This allows your display to calculate True Wind data, including VMG. This gives good results
// as long as there no current.
#define EMULATE_SPD_WITH_SOG 0

// Define which compass axis will be compared to magnetic north
// Set one of the (X, Y, Z) to 1.0 or -1.0
#define HEADING_AXIS                                                                                                                                 \
    {                                                                                                                                                \
        1.0f, 0.0f, 0.0f                                                                                                                             \
    }

/***************************************************************************/
/*                                Types                                    */
/***************************************************************************/

/***************************************************************************/
/*                              Prototypes                                 */
/***************************************************************************/

#endif /* BOARDCONFIG_H_ */

[j-lang]

Only this parameter was changed:
#define NMEA_EXT WIRED_NMEA
Board: Teensy 4.0 with bluetooth serial adapter on serial 2. PCB from here: https://github.com/Rodemfr/MicronetToNMEA/tree/master/hardware/v1

[Rodemfr]

I made additional tests today. It is still working fine for me. However, I compared your BoardConfig.h to mine and I see that your GNSS & NMEA_EXT serials have been swapped. Also GDO0 pin in changed. There is nothing illegal there but it could be that MTN is doing something wrong with these pins leading to problems when you connect NMEA_EXT to the WIRED_NMEA serial link.
I quickly read the code and did not find any hardcoded access to serial pins. I will review the code again later with a fresh mind...

[j-lang]

Thank you, I will connect a serial to usb adapter to NMEA_EXT and will check all again within the next days.

[j-lang]

Ok, rechecked it:
as long there is no GPS fix: RMC, VTG and GGA are sent out to WIRED_NMEA (#define NMEA_EXT WIRED_NMEA).
with GPS fix only RMC and VTG are sent out to WIRED_NMEA!
This issue is valid for bitrates up to 19200. If the WIRED_NMEA is set to 38400 bit/s or higher, also the GGA messages are sent out on GPS fix.

[Rodemfr]

I had a look to HardwareSerial.cpp to understand how Teensy SW stack is handling data. I noticed that the serial buffer is pretty small (64 bytes).
Your problem could be explained by the fact that GGA exceeds 64 bytes when fix is acquired.
I suspect that at 38400 & above, sending speed is high enough to empty the TX buffer before it is full while it is not below.

You can check that by changing SERIAL1_TX_BUFFER_SIZE from 64 to let say 128 or 256 in file HardwareSerial1.cpp of Teensy SW stack. If it works at 19200, then that's the explanation and you will have no other choice than raising your communication speed to 38400 or higher.

[j-lang]

OK; I will check ist.
By the way: I am currently writing some code to configure the HC-06 Bluetooth interface: baud rate and name.
So it is possible to configure the module without desoldering.
It will take some days, then the module can be set to higher bitrates.

[Rodemfr]

That would be an excellent addition to MTN !