Receiving No Data

Viewing 10 posts - 1 through 10 (of 10 total)
  • Author
    Posts
  • #16549
    musch711
    Participant

    Hi,

    I’m trying to connect the Berry GPS-IMU to a Raspberry Pi 4 using the QWIIC connector.  The led on the GPS is lit green, but I’m receiving no data on serial0 (using cat /dev/serial0 hangs).  I’ve included some diagnostic output below.  I’d appreciate any suggestions or advice.

    Thanks,

    Steven

    pi@raspberrypi:~ $ dmesg | grep tty
    [ 0.000000] Kernel command line: coherent_pool=1M 8250.nr_uarts=1 snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 video=HDMI-A-1:1920x1080M@60,margin_left=48,margin_right=48,margin_top=48,margin_bottom=48 smsc95xx.macaddr=DC:A6:32:D5:5D:CE vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000 console=tty1 root=/dev/mmcblk0p7 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet splash plymouth.ignore-serial-consoles
    [ 0.001057] printk: console [tty1] enabled
    [ 1.238296] fe201000.serial: ttyAMA0 at MMIO 0xfe201000 (irq = 29, base_baud = 0) is a PL011 rev2
    [ 1.244976] fe215040.serial: ttyS0 at MMIO 0x0 (irq = 30, base_baud = 62500000) is a 16550

    #16550
    Mark Williams
    Keymaster

    You will need to have the BerryGPS-IMU sitting ontop of the Raspberry Pi GPIO to get access to the GPS data via serial

    Mark --OzzMaker.com --

    #16551
    musch711
    Participant

    Hi Mark,

    I thought according to this, the QWIIC connector could serve as an alternative instead of mounting the IMU directly on top and soldering the connection.  Is that not accurate?

    Thanks,

    Steven

    #16552
    Mark Williams
    Keymaster

    Sorry if it wasn’t clear.  ill make sure that page gets updated.

    If you connect via QWIIC connector only, you would only be able to access the GPS module via i2c (you would need to solder a couple of jumpers on the back to enable this function).   This means you would not be able to use GPSD as GSPD relies on serial.  We are trying to come up with a way to make it work with GPSD via i2c.

    You can however, get lon,lat, speed, etc.. via i2c using

     
    Here is some python code I have been playing around with;

    import time
    import json
    import smbus
    import logging 
    BUS = None
    address = 0x42
    gpsReadInterval = 0.1
    LOG = logging.getLogger()
    GPSDAT = {
        'strType': None,
        'fixTime': None,
        'lat': None,
        'latDir': None,
        'lon': None,
        'lonDir': None,
        'fixQual': None,
        'numSat': None,
        'horDil': None,
        'alt': None,
        'altUnit': None,
        'galt': None,
        'galtUnit': None,
        'DPGS_updt': None,
        'DPGS_ID': None
    }
    def connectBus():
        global BUS
        BUS = smbus.SMBus(1)
    def parseResponse(gpsLine):
        global lastLocation
        gpsChars = ''.join(chr(c) for c in gpsLine)
        if "*" not in gpsChars:
            return False
        gpsStr, chkSum = gpsChars.split('*')    
        gpsComponents = gpsStr.split(',')
        gpsStart = gpsComponents[0]
        if (gpsStart == "$GNGGA"):
            chkVal = 0
            for ch in gpsStr[1:]: # Remove the $
                chkVal ^= ord(ch)
            if (chkVal == int(chkSum, 16)):
                '''for i, k in enumerate(
                    ['strType', 'fixTime', 
                    'lat', 'latDir', 'lon', 'lonDir',
                    'fixQual', 'numSat', 'horDil', 
                    'alt', 'altUnit', 'galt', 'galtUnit',
                    'DPGS_updt', 'DPGS_ID']):
                    GPSDAT[k] = gpsComponents'''
                print gpsChars
                #print json.dumps(GPSDAT, indent=2)
    def readGPS():
        c = None
        response = []
        try:
            while True: # Newline, or bad char.
                c = BUS.read_byte(address)
                if c == 255:
                    return False
                elif c == 10:
                    break
                else:
                    response.append(c)
            parseResponse(response)
        except IOError:
            time.sleep(0.5)
            connectBus()
        except Exception, e:
            print e
            LOG.error(e)
    connectBus()
    while True:
        readGPS()
        time.sleep(gpsReadInterval)

    Mark --OzzMaker.com --

    #16556
    musch711
    Participant

    Hi Mark,

    Thanks for the follow up with code sample!  I enabled i2c and was able to get some readings from it; however, given what you mentioned about additional soldering for GPS, I’m currently limited to the accelerometer.  I used the following code: https://github.com/ozzmaker/BerryIMU/blob/master/python-BerryIMU-gryo-accel-compass/berryIMU-simple.py to get the reading.

    Thank you for your help and I’ll follow up if I have additional questions!

    -Steven

    #16649
    vovacooper
    Participant

    Hi Mark,
    i got the V4 GPS-IMU module, trying to connect it to Jetson via qwiic (i2c), all working well but the GPS :(.

    i saw that u wrote “If you connect via QWIIC connector only, you would only be able to access the GPS module via i2c (you would need to solder a couple of jumpers on the back to enable this function)…”

    Unfortunately i cant find any place that specifies which jumpers i need to solder.

    Can u please explain which jumpers i need to solder for the GPS to start working via I2C?

    Thanks

    #16655
    Mark Williams
    Keymaster

    Hi, we are in the middle of writing up a guide on this, it should be posted soon.
    But, in summary.. its JP7& JP8

    Mark --OzzMaker.com --

    #16657
    vovacooper
    Participant

    Sorry to bother you but its very frustrating that you just writing a guid on a product i already have…

    It looks like the JP7 and JP8 is has a connection already (without soldering)…
    Do i need to there it off?

    do i need to connect JP7 to JP8?

    What should i do to make the GPS work with I2C?

    thanksJP7 + JP8

    #16658
    vovacooper
    Participant

    found it 🙂

    it was JP10 + JP11 and not JP7 + JP8

    🙁

     

    #16659
    richardp
    Participant

    You are right!  I am so sorry.. not sure what I was looking at 🙁

Viewing 10 posts - 1 through 10 (of 10 total)
  • You must be logged in to reply to this topic.

Blip, blop, bloop…