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Merge pull request #46 from aberridg/add-esp32-spi-example
Add ESP32 SPI example - thank you @aberridg
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/*
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Reading lat and long via UBX binary commands over SPI (ESP32 specific example)
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By: Andrew Berridge
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Date: 27th June 2021
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License: MIT. See license file for more information but you can
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basically do whatever you want with this code.
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This example shows how to query a u-blox module for its lat/long/altitude over SPI. We also
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turn off the NMEA output on the SPI port. This decreases the amount of SPI traffic
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dramatically.
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Note: Long/lat are large numbers because they are * 10^7. To convert lat/long
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to something google maps understands simply divide the numbers by 10,000,000. We
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do this so that we don't have to use floating point numbers.
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Leave NMEA parsing behind. Now you can simply ask the module for the datums you want!
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Feel like supporting open source hardware?
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Buy a board from SparkFun!
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ZED-F9P RTK2: https://www.sparkfun.com/products/15136
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NEO-M8P RTK: https://www.sparkfun.com/products/15005
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SAM-M8Q: https://www.sparkfun.com/products/15106
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Hardware Connections:
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You need to connect the SPI pins from your microcontroller to the specific pins on your SparkFun product.
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Connections will vary based on your microcontroller, but for reference please refer to this tutorial on SPI:
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https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi/all
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Most new boards now use the terms:
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CS - Chip Select
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COP - Controller Out, Peripheral In
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CIPO - Controller in, Peripheral Out
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SCK - Serial Clock
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You can choose any pin for Chip Select, but the others are likely either defined by the library you are using
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(see here for the standard Arduino one: https://www.arduino.cc/en/reference/SPI) or the microcontroller. The
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ESP32 has two standard, selectable SPI ports, for example.
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IMPORTANT: there have been reports that some ublox devices do not respond to the UBX protocol over SPI
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with the factory settings. You may find you need to connect to the device via USB and u-center and set
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the incoming protocol to UBX only. Make sure you disable all other protocols as inputs if you can't
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get things to work! Hopefully this is just a bug in the ublox firmware that will be fixed soon ;-)
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*/
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#include <SPI.h> //Needed for SPI to GNSS
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#include <SparkFun_u-blox_GNSS_Arduino_Library.h> //http://librarymanager/All#SparkFun_u-blox_GNSS
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SFE_UBLOX_GNSS myGNSS;
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// Instantiate an instance of the SPI class.
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// This is the default ESP32 SPI interface. Your configuration may be different, depending on the microcontroller you are using!
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SPIClass spiPort (HSPI);
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const uint8_t csPin = 15; // Change this to suit your own connection for the chip select pin
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long lastTime = 0; //Simple local timer. Limits amount of SPI traffic to u-blox module.
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void setup()
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{
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Serial.begin(115200);
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while (!Serial); //Wait for user to open terminal
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Serial.println("SparkFun u-blox Example");
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spiPort.begin();
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myGNSS.setFileBufferSize(100); // set the file buffer size
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// Connect to the u-blox module using SPI port, csPin and speed setting
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// ublox devices generally work up to 5Mhz. We'll use 4Mhz for this example:
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if (myGNSS.begin(spiPort, csPin, 4000000) == false)
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{
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Serial.println(F("u-blox GNSS not detected on SPI bus. Please check wiring. Freezing."));
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while (1);
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}
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myGNSS.disableMessage(UBX_CLASS_HNR, UBX_HNR_PVT, 0x04);
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myGNSS.disableMessage(UBX_CLASS_HNR, UBX_HNR_ATT, 0x04);
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myGNSS.disableMessage(UBX_CLASS_HNR, UBX_HNR_INS, 0x04);
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myGNSS.setAutoPVT(false); //Tell the GNSS to "send" each solution
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myGNSS.setPortInput(COM_PORT_SPI, COM_TYPE_UBX); //Set the SPI port to output UBX only (turn off NMEA noise)
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myGNSS.saveConfigSelective(VAL_CFG_SUBSEC_IOPORT); //Save (only) the communications port settings to flash and BBR
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}
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void loop()
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{
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//Query module only every second. Doing it more often will just cause SPI traffic.
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//The module only responds when a new position is available
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if (millis() - lastTime > 1000)
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{
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lastTime = millis(); //Update the timer
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long latitude = myGNSS.getLatitude();
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Serial.print(F("Lat: "));
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Serial.print(latitude);
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long longitude = myGNSS.getLongitude();
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Serial.print(F(" Long: "));
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Serial.print(longitude);
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Serial.print(F(" (degrees * 10^-7)"));
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long altitude = myGNSS.getAltitude();
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Serial.print(F(" Alt: "));
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Serial.print(altitude);
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Serial.print(F(" (mm)"));
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byte SIV = myGNSS.getSIV();
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Serial.print(F(" SIV: "));
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Serial.print(SIV);
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Serial.println();
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}
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}

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