Pytrack and GPS Balloon mode

[brunoS]

Hello,

For a stratospheric balloon project, I'm going to ship a Pytrack card.
But for the I76 GPS to operate at high altitude, it is necessary to activate the "balloon mode" :

Quectel_L76_Series_Protocol_Specification_V2.0

Therefore, send a frame $PMTK886,32B <CR> <LF> and wait for the answer $PMTK001,886,336.

Has any of you tested and managed to send a frame to the Pytrack GPS module so that I do not start from scratch?

Thanks for your help

[this.wiederkehr]

sorry no clue, I am not using pycom devices anymore so I can't tell. Sorry.

[Alex Dew]

@this-wiederkehr Has anything changed with this? When I run the exact same thing, I do not get any 001 response.

[this.wiederkehr]

@brunos: I think the application note of the gps ( there is one regarding i2c) mentioned to perform a dummy write like this. But I dont have that at hand right now...

[brunoS]

@this-wiederkehr

Thank you for the quick reply !
I tested and I saw well the answer in the flow of the frames.
What is the purpose of the line :

self.i2c.writeto(GPS_I2CADDR, bytes([0])) 

[this.wiederkehr]

@brunoS

class L76GNSS:
    def __init__(self, py=None, sda='P22', scl='P21', writer=None):
        if py is not None:
            self.i2c = py.i2c
        else:
            from machine import I2C
            self.i2c = I2C(0, mode=I2C.MASTER, pins=(sda, scl))
        GPS_CONFIG = b'$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n'
        self.i2c.writeto(GPS_I2CADDR, GPS_CONFIG)
        self.i2c.writeto(GPS_I2CADDR, bytes([0]))
        ....

That is what I added in the init method to restrict sentence output. Be sure to have the correct checksum.