Tag Archives: UART

In this video lesson I show how to get usable Latitude and Longitude from the Adafruit Ultimate GPS version 3 using the Raspberry Pi Pico W. We read the NMEA sentences from the GPS, we parse them into individual strings for each sentence, and then we create arrays of data from the strings. Then we begin to parse the arrays, and convert the confusing numbers into useful Decimal Degree values for Latitude and Longitude.

Pi Pico GPS — This schematic shows how to connect the Adafruit Ultimate GPS to the Raspberry Pi Pico W

For your convenience, this is the code we developed in todays lesson:

from machine import Pin,I2C,UART  #***************
import time
GPS = UART(1, baudrate=9600, tx=machine.Pin(8), rx=machine.Pin(9))
# The following line ensures that the GPS reports the GPVTG NMEA Sentence
GPS.write(b"$PMTK314,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n")
myNMEA=""
GPGGA=""
GPGSA=""
GPRMC=""
GPVTG=""
GPGSV=""
while not GPS.any():
    pass
while GPS.any():
    junk=GPS.read()
    print(junk)
try:
    while True:
        if GPS.any():
            #myChar=GPS.read(1)
            myChar=GPS.read(1).decode('utf-8')
            myNMEA=myNMEA+myChar
            if myChar=='\n':
                if myNMEA[1:6]=="GPGGA":
                    GPGGA=myNMEA
                    GPGGAarray=GPGGA.split(',')
                    #print(GPGGA)
                    #print(GPGGAarray)
                    if int(GPGGAarray[6]) != 0:
                        latRAW=GPGGAarray[2]
                        lonRAW=GPGGAarray[4]
                        numSat=int(GPGGAarray[7])
                        latDD=int(latRAW[0:2])+float(latRAW[2:])/60
                        lonDD=int(lonRAW[0:3])+float(lonRAW[3:])/60
                        if GPGGAarray[3]=='S':
                            latDD=-latDD
                        if GPGGAarray[5]=='W':
                            lonDD=-lonDD
                        print("LAT, LON, numSat ",latDD,lonDD,numSat)
                if myNMEA[1:6]=="GPGSA":
                    GPGSA=myNMEA
                    GPGSAarray=GPGSA.split(',')
                if myNMEA[1:6]=="GPRMC":
                    GPRMC=myNMEA
                    GPRMCarray=GPRMC.split(',')
                    knots=float(GPRMCarray[7])
                    heading=float(GPRMCarray[8])
                    print(knots, "Knots at a Heading of: ",heading)
                if myNMEA[1:6]=="GPVTG":
                    GPVTG=myNMEA
                    GPVTGarray=GPVTG.split(',')
                if myNMEA[1:6]=="GPGSV":
                    GPGSV=myNMEA
                    GPGSVarray=GPGSV.split(',')
                    if GPGGA!="":
                        if int(GPGGAarray[6])==0:
                            print('Aquiring Fix:', GPGSVarray[3], "Sattellites in View")
                                              
                myNMEA=""
except KeyboardInterrupt:
    print("\nStopping program... Cleaning up UART.")
    GPS.deinit()  # Properly release UART before exit
    time.sleep(1)  # Short pause to ensure clean shutdown
    print("Exited cleanly.")

from machine import Pin,I2C,UART #***************

import time

GPS = UART(1, baudrate=9600, tx=machine.Pin(8), rx=machine.Pin(9))

# The following line ensures that the GPS reports the GPVTG NMEA Sentence

GPS.write(b"$PMTK314,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n")

myNMEA=""

GPGGA=""

GPGSA=""

GPRMC=""

GPVTG=""

GPGSV=""

while not GPS.any():

pass

while GPS.any():

junk=GPS.read()

print(junk)

try:

while True:

if GPS.any():

#myChar=GPS.read(1)

myChar=GPS.read(1).decode('utf-8')

myNMEA=myNMEA+myChar

if myChar=='\n':

if myNMEA[1:6]=="GPGGA":

GPGGA=myNMEA

GPGGAarray=GPGGA.split(',')

#print(GPGGA)

#print(GPGGAarray)

if int(GPGGAarray[6]) != 0:

latRAW=GPGGAarray[2]

lonRAW=GPGGAarray[4]

numSat=int(GPGGAarray[7])

latDD=int(latRAW[0:2])+float(latRAW[2:])/60

lonDD=int(lonRAW[0:3])+float(lonRAW[3:])/60

if GPGGAarray[3]=='S':

latDD=-latDD

if GPGGAarray[5]=='W':

lonDD=-lonDD

print("LAT, LON, numSat ",latDD,lonDD,numSat)

if myNMEA[1:6]=="GPGSA":

GPGSA=myNMEA

GPGSAarray=GPGSA.split(',')

if myNMEA[1:6]=="GPRMC":

GPRMC=myNMEA

GPRMCarray=GPRMC.split(',')

knots=float(GPRMCarray[7])

heading=float(GPRMCarray[8])

print(knots, "Knots at a Heading of: ",heading)

if myNMEA[1:6]=="GPVTG":

GPVTG=myNMEA

GPVTGarray=GPVTG.split(',')

if myNMEA[1:6]=="GPGSV":

GPGSV=myNMEA

GPGSVarray=GPGSV.split(',')

if GPGGA!="":

if int(GPGGAarray[6])==0:

print('Aquiring Fix:', GPGSVarray[3], "Sattellites in View")

myNMEA=""

except KeyboardInterrupt:

print("\nStopping program... Cleaning up UART.")

GPS.deinit() # Properly release UART before exit

time.sleep(1) # Short pause to ensure clean shutdown

print("Exited cleanly.")

MicroPython, Raspberry Pi Pico

Incorporating an Adafruit Ultimate GPS into your Raspberry Pi Pico W Project

May 2, 2025 admin

In this video lesson we will show you how to connect and begin to get data from your Raspberry Pi Pico W connected to an Adafruit Ultimate GPS. The circuit schematic presented below. Notice Tx on the Pi Pico goes to Rx on the GPS, and Rx on the Pi Pico goes to Tx on the GPS.

Then this is our initial code which reads the data from the GPS one byte at a time and prints it. In future lessons we will explain how to get useful information from this data, but for now, this code will allow you to read the data:

from machine import Pin,I2C,UART
import time

GPS = UART(1, baudrate = 9600, tx=machine.Pin(8), rx=machine.Pin(9))

try:
    while True:
        if GPS.any():
            myChar=GPS.read(1).decode('utf-8')
            print(myChar, end="")
    
except KeyboardInterrupt:
    print("\n . . . Cleaning Up UART")
    GPS.deinit()
    time.sleep(1)
    print("Cleanly Exited UART")

from machine import Pin,I2C,UART

import time

GPS = UART(1, baudrate = 9600, tx=machine.Pin(8), rx=machine.Pin(9))

try:

while True:

if GPS.any():

myChar=GPS.read(1).decode('utf-8')

print(myChar, end="")

except KeyboardInterrupt:

print("\n . . . Cleaning Up UART")

GPS.deinit()

time.sleep(1)

print("Cleanly Exited UART")

Beaglevone Black Rev. C, Tutorial

Beaglebone Black GPS LESSON 2: Sending Commands to the Adafruit GPS Module

June 15, 2015 admin

In lesson 1 we showed you how to connect the Adafruit Ultimate GPS breakout board to the Beaglebone Black and how to read the NMEA sentences streaming off the GPS over the UART pins. In this lesson we will show you how to send commands to the GPS to better tailor its operation for our needs. There are a number of commands that can be sent to it. Some of the things we we can control are the baud rate it communicates at, and the rate that it takes and sends data. We can also influence which NMEA sentences it sends. In this video we will go over the different commands we can use.

To review, you should connect the GPS as follows:

Beaglebone GPS — Adafruit Ultimate GPS connected to the Beaglebone Black Rev C Microcontroller

The video explains the code step-by-step, but here it is for your reference.

import serial #import pyserial library
import Adafruit_BBIO.UART as UART #import UART Library
UART.setup("UART1")  #Initialize UART1
ser=serial.Serial('/dev/ttyO1',9600) #Initialize Serial Port
from time import sleep #import sleep library
class GPS:                      #Create GPS class
        def __init__(self):     #This init will run when you create a GPS object.
                #This sets up variables for useful commands.
                #This set is used to set the rate the GPS reports
                UPDATE_10_sec=  "$PMTK220,10000*2F\r\n" #Update Every 10 Seconds
                UPDATE_5_sec=  "$PMTK220,5000*1B\r\n"   #Update Every 5 Seconds  
                UPDATE_1_sec=  "$PMTK220,1000*1F\r\n"   #Update Every One Second
                UPDATE_200_msec=  "$PMTK220,200*2C\r\n" #Update Every 200 Milliseconds
                #This set is used to set the rate the GPS takes measurements
                MEAS_10_sec = "$PMTK300,10000,0,0,0,0*2C\r\n" #Measure every 10 seconds
                MEAS_5_sec = "$PMTK300,5000,0,0,0,0*18\r\n"   #Measure every 5 seconds
                MEAS_1_sec = "$PMTK300,1000,0,0,0,0*1C\r\n"   #Measure once a second
                MEAS_200_msec= "$PMTK300,200,0,0,0,0*2F\r\n"  #Meaure 5 times a second
                #Set the Baud Rate of GPS
                BAUD_57600 = "$PMTK251,57600*2C\r\n"          #Set Baud Rate at 57600
                BAUD_9600 ="$PMTK251,9600*17\r\n"             #Set 9600 Baud Rate
                #Commands for which NMEA Sentences are sent
                GPRMC_ONLY= "$PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*29\r\n" #Send only the GPRMC Sentence
                GPRMC_GPGGA="$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n"#Send GPRMC AND GPGGA Sentences
                SEND_ALL ="$PMTK314,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n" #Send All Sentences
                SEND_NOTHING="$PMTK314,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n" #Send Nothing
                ser.write(BAUD_57600)   #Set Baud Rate to 57600
                sleep(1)                #Paulse
                ser.baudrate=57600      #IMPORTANT Since change ser baudrate to match GPS
                ser.write(UPDATE_200_msec) #Set update rate
                sleep(1)
                ser.write(MEAS_200_msec)  #Set measurement rate
                sleep(1)
                ser.write(GPRMC_GPGGA)    #Ask for only GPRMC and GPGGA Sentences
                sleep(1)
                ser.flushInput()          #clear buffers
                ser.flushOutput()
                print "GPS is Initialized" #Print message

myGPS=GPS()
while(1):
        ser.flushInput() #Clear Buffers
        ser.flushInput()
        while ser.inWaiting()==0: #Wait for input
                pass
        NMEA1=ser.readline()      #Read NMEA1
        while ser.inWaiting()==0:
                pass
        NMEA2=ser.readline()
        print NMEA1
        print NMEA2

import serial #import pyserial library

import Adafruit_BBIO.UART as UART #import UART Library

UART.setup("UART1") #Initialize UART1

ser=serial.Serial('/dev/ttyO1',9600) #Initialize Serial Port

from time import sleep #import sleep library

class GPS: #Create GPS class

def __init__(self): #This init will run when you create a GPS object.

#This sets up variables for useful commands.

#This set is used to set the rate the GPS reports

UPDATE_10_sec= "$PMTK220,10000*2F\r\n" #Update Every 10 Seconds

UPDATE_5_sec= "$PMTK220,5000*1B\r\n" #Update Every 5 Seconds

UPDATE_1_sec= "$PMTK220,1000*1F\r\n" #Update Every One Second

UPDATE_200_msec= "$PMTK220,200*2C\r\n" #Update Every 200 Milliseconds

#This set is used to set the rate the GPS takes measurements

MEAS_10_sec = "$PMTK300,10000,0,0,0,0*2C\r\n" #Measure every 10 seconds

MEAS_5_sec = "$PMTK300,5000,0,0,0,0*18\r\n" #Measure every 5 seconds

MEAS_1_sec = "$PMTK300,1000,0,0,0,0*1C\r\n" #Measure once a second

MEAS_200_msec= "$PMTK300,200,0,0,0,0*2F\r\n" #Meaure 5 times a second

#Set the Baud Rate of GPS

BAUD_57600 = "$PMTK251,57600*2C\r\n" #Set Baud Rate at 57600

BAUD_9600 ="$PMTK251,9600*17\r\n" #Set 9600 Baud Rate

#Commands for which NMEA Sentences are sent

GPRMC_ONLY= "$PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*29\r\n" #Send only the GPRMC Sentence

GPRMC_GPGGA="$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n"#Send GPRMC AND GPGGA Sentences

SEND_ALL ="$PMTK314,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n" #Send All Sentences

SEND_NOTHING="$PMTK314,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n" #Send Nothing

ser.write(BAUD_57600) #Set Baud Rate to 57600

sleep(1) #Paulse

ser.baudrate=57600 #IMPORTANT Since change ser baudrate to match GPS

ser.write(UPDATE_200_msec) #Set update rate

sleep(1)

ser.write(MEAS_200_msec) #Set measurement rate

sleep(1)

ser.write(GPRMC_GPGGA) #Ask for only GPRMC and GPGGA Sentences

sleep(1)

ser.flushInput() #clear buffers

ser.flushOutput()

print "GPS is Initialized" #Print message

myGPS=GPS()

while(1):

ser.flushInput() #Clear Buffers

ser.flushInput()

while ser.inWaiting()==0: #Wait for input

pass

NMEA1=ser.readline() #Read NMEA1

while ser.inWaiting()==0:

pass

NMEA2=ser.readline()

print NMEA1

print NMEA2

This code sets the GPS to communicate at baud rate of 57600, and set it to read and report 5 readings a second. It then sets the GPS to only report the $GPRMC and the $GPGGA sentences. It then constantly reads and reports the NMEA sentences.

Technology Tutorials

Tag Archives: UART

Getting Latitude and Longitude from the Adafruit Ultimate GPS with Raspberry Pi Pico W

Incorporating an Adafruit Ultimate GPS into your Raspberry Pi Pico W Project

Beaglebone Black GPS LESSON 2: Sending Commands to the Adafruit GPS Module

Making The World a Better Place One High Tech Project at a Time. Enjoy!