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Make it with Micromite Phil Boyce – hands on with the mighty PIC-powered, BASIC microcontroller Part 45: Updating the PicoMite firmware D uring development of the PicoMite Fingerprint Reader (our current Make it with Micromite project), a new version of the PicoMite firmware was released. Normally, we would simply make you aware that a new version of MMBASIC was available, allowing you to update your PicoMite(s) as and when convenient. However, in this latest release, there are some fundamental changes to the way the PicoMite behaves (as well as the usual performance improvements, and some new commands). One noticeable change concerns the storage (and subsequent access) of program files, data files, image files and sound files. Traditionally, if required, files would be stored on an attached SD card; however, this new firmware allows files to be also stored in the PicoMite’s own internal Flash memory. This new feature is something that we should be able to benefit from in the Fingerprint Reader, and hence this firmware update should be regarded as an essential requirement for your PicoMite(s). Therefore, we will begin this month with a quick explanation of how to upgrade your PicoMite(s) with this latest release of MMBASIC, and then we will discuss the hardware required to build the Fingerprint Reader. We will explain how to configure the required OPTIONs to ensure that the new firmware is able to access the SD card; and we will finish by loading a simple test program to ensure that everything is connected correctly. Let’s begin by downloading the required files. PicoMite v5.07.06 Just two files need to be downloaded: the firmware file (PicoMiteV5.07.06. uf2), and the User Manual (PicoMite_ User_Manual.pdf). These are both available for free download by visiting: https://geoffg.net/picomite.html Simply scroll down to the ‘Downloads’ section (located towards the bottom of 50 Fig.1. To see what OPTIONs have been set, use the OPTION LIST command. the page) and click on the DOWNLOAD button which is next to the description: PicoMite firmware V5.07.06 (includes the above manual). This will download a zipped folder from which you can unzip (extract) the two required files. Alternatively, you can download them both from the March 2023 page of the PE website: https://bit.ly/pe-downloads Once you have these two files, store them in a convenient folder on your computer. I tend to leave the .uf2 file in the Downloads folder, and put the User Manual in the Documents folder. Uploading the firmware This process was covered in MIWM Part 35 (PE, April 2022); however, since it’s a quick-and-easy process, we will cover the steps again here. Note that it should take you less than a minute to complete the upload. However, if you’re upgrading from a previous version of MMBASIC, then before you begin, there are two points to consider. First, if you are currently working on a project and you simply want to upgrade to this latest version of MMBASIC, then ensure that you make a note of any OPTIONs that you currently have set. This is because this firmware upgrade will wipe out all existing OPTIONs – you have been warned! The best way to do this is, at the command prompt, type OPTION LIST and then simply take a screen grab (or photo) of what is displayed. (See Fig.1 for an example list of OPTIONs). Second, if you have any program code that you wish to keep, do back it up. To do this, at the command prompt, type LIST ALL and then (for TeraTerm) simply highlight the code displayed (to copy it onto the Windows clipboard), and then paste it into something like Notepad (or any other text editor). Next, save the Notepad file with a suitable filename into an appropriate folder. After saving any important information, you can now perform the firmware upload by following these four steps: 1. Begin by disconnecting the PicoMite from your computer (ie, remove power to the PicoMite). 2. Press the BOOTSEL button (on the PicoMite) and hold it down as you plug the PicoMite into the USB port. This will result in the Pico powering up into what is known as ‘Bootloader Mode’ – it will appear to the computer as an additional USB Flash drive. This is signified by a new ‘Pico Drive’ Window automatically displayed on your computer (see Fig.2). NOTE: Do not delete either of the two files currently in the ‘Pico Drive’. 3. Paste (or drag / drop) the downloaded firmware file (PicoMiteV5.07.06.uf2) into the ‘Pico Drive’. This will immediately start the upload process, and a progress bar will appear briefly (see Fig.3) 4. Once the upload is finished, remove the PicoMite, then re-insert it and start up your preferred Terminal program. You should now see the firmware has been upgraded to version v5.07.06, as indicated in the PicoMite’s power-up ‘Welcome message’ (see Fig.4) Practical Electronics | March | 2023 Fig.2. If the BOOTSEL button is pressed while connecting the Pico to a computer, this ‘Pico Drive’ window will automatically appear. Fig.3. When the .uf2 firmware file is moved into the Pico Drive, it will automatically be processed, during which time a progress bar is displayed. Fig.4. (left) Here, the PicoMite’s welcome message (displayed at power-up) confirms that MMBASIC has been upgrade to version v5.07.06. Fig.6. Our preferred RTC module. It will capture the time/date of a finger detection. Fig.7. The R503 capacitive fingerprint sensor module. This was covered in detail in Parts 1 (PE, December 2022) and Parts 2 of the project (PE, February 2023). With the firmware upload complete, you can now proceed to set OPTIONs as required. However, if the upgrade failed, then simply repeat the above four steps again. The most common issue is with step 2 if the BOOTSEL button isn’t pressed at the time the PicoMite is powered up. If you don’t see the ‘Pico Drive’ window appear shortly after you insert the PicoMite, then re-insert it with the button firmly pushed. Fingerprint Reader hardware The completed unit will comprise of the following four hardware modules: 1. PicoMite 2. 2 .8-inch Touchscreen (Waveshare PicoRes Touch-LCD-2.8) – see Fig.5 3. Mini Real-Time Clock (RTC) module (Fig.6) 4. R503 Fingerprint module (Fig.7) To assist with development, a Pico expander module (see Fig.8) will also be useful to link everything together. We will use one to initially check that everything works as expected. Note that the Touchscreen module also comes with Fig.5. (Left and above) Front/rear views of the Waveshare 2.8-inch touchscreen module. Its three advantages are: low cost, based on IPS technology (better image than normal TFTs), and it has an onboard SD socket. Practical Electronics | March | 2023 Fig.8. A Pico Expander module will simplify the connections to all the hardware elements. an onboard micro-SD socket which we will also be using in the Fingerprint Reader. All connections are shown in Fig.9, and this will prove useful when it comes to connecting the RTC and R503 modules. It will also help clarify the parameters we’ll be using when setting the required OPTIONs. Begin assembly by plugging the PicoMite into the Pico expander, taking care to align the micro-USB socket on the PicoMite with that shown on the Pico expander. (Note that the PicoMite should not be powered up at this stage.) Next, carefully insert the Waveshare module into a convenient place on the Pico expander, ensure you align the USB silkscreen on the display module with that on the Pico expander. 51 R503 RX GP0 1 40 VBUS R503 TX GP1 2 39 VSYS GND 3 38 GND GP2 4 37 3V3EN GP3 5 36 3V3 GP4 6 35 ADC REF GP5 7 34 GP28 GND 8 33 GND GP6 9 32 GP27 GP7 10 31 GP26 TFT DC GP8 11 30 RUN TFT CS GP9 12 29 GP22 GND 13 28 GND R503 Finger detect Fig.9. The Fingerprint Reader hardware is based around the PicoMite. All connections to it are summarised here. n  GUI SD CS SPI CLK (TFT/SD) GP10 14 27 GP21 I2C CLOCK (RTC) SPI MOSI (TFT/SD) GP11 15 26 GP20 I2C DATA (RTC) SPI MISO (TFT/SD) GP12 16 25 GP19 TFT Backlight PWM GP13 17 24 GP18 GND 18 23 GND GP14 19 22 GP17 TOUCH IRQ GP15 20 21 GP16 TOUCH CS TFT Reset R503 (fingerprint module) Red 3V3 Black GND Yellow Tx Green Rx Bue Finger detect White Induction power 3V3 0V GP1 GP0 RTC 3V3 With the PicoMite connected to your computer, launch your preferred terminal program. At the command prompt, work through the following steps to configure each required OPTION: n O PTION CPUSPEED 252000 – this ensures that the PicoMite runs at 252MHz. n OPTION SYSTEM I2C GP20,GP21 – defines the I2C pins (SDA and SCL) that connect to the RTC module’s D and C pins. n OPTION SYSTEM SPI GP10,GP11,GP12 – defines the SPI pins (CLK, MOSI, MISO) that connect to the TFT and the SD. n OPTION LCDPANEL ST7789_320,L,GP8,GP15,GP9,GP13 – defines the TFT pins (DC, RST, CS and Backlight) as used by the TFT module. Fig.10. By default (on power-up), the FILES command will show any files stored on the internal Flash drive (Drive A). 52 3V3 D GP20 C GP21 – 0V GP2 The mini-RTC module can be connected by using four female-male DuPont leads. Pin D (I 2C Data) on the RTC connects to GP20, and pin C (I2C Clock) connects to GP21. It is connected to 3.3V (and not 5V). The R503 module is also connected to 3.3V, and to the PicoMite’s COM1 pins on GP0 and GP1 (refer to Fig.9). The ‘Finger Detect’ output signal is connected to GP2. With all the modules connected to each other, we can now proceed to configure the required OPTIONs so that we can then test everything is connected correctly. Configuring OPTIONs 3V3 + T E S T L C D P A N E L – draws multiple, colourful overlapping circles to confirm that the TFT is configured correctly. It will continue until you press a key on your terminal application. If nothing appears, it is likely that a parameter in OPTION LCDPANEL is incorrect (in which case, enter OPTION LCDPANEL DISABLE and carefully re-key the above step with the correct parameters). n  OPTION TOUCH GP16,GP17 – defines the touch panel’s CS and IRQ pins. n  GUI CALIBRATE – follow the onscreen instructions to calibrate the touchscreen (touch the four crosshairs in turn). n  GUI TEST TOUCH – this should draw a dot at the exact point that you touch the screen. Use a plastic stylus for this process so that you can confirm the accuracy of calibration. If the dot is not accurately placed, press any key to exit the test, and repeat the GUI CALIBRATE command. n  OPTION SDCARD GP22 – defines the pin that connects to the SD card’s CS pin Having configured the SD card, we would normally test it with the FILES command which will display the names of any files stored on the inserted SD card. However, if you try the FILES command now, you will see a different result – see Fig.10. This relates to the new feature of file storage mentioned at the beginning of this article. By default (at power up) the FILES command will show the files that are stored in the PicoMite’s own internal Flash memory (which can be regarded as an inbuilt Flash drive). So, how do we now access files stored on the SD card? The DRIVE command There are now two locations that the PicoMite can store files: the new Flash drive (built into the PicoMite’s internal Flash memory), and an external SD card (if defined by Fig.11. The DRIVE “B:” command is used to switch focus to the SD card. Practical Electronics | March | 2023 Fig.12. This is the ‘splash’ screen that will be displayed when the Fingerprint Reader is powered up. Also used in the Flash drive demonstration. using the OPTION SDCARD command as we have done above). The Flash drive is referred to as ‘Drive-A’, and the SD card is ‘Drive-B’. To switch between them you simply use the new command DRIVE. So, to select the SD card, simply type DRIVE “B:” after which any subsequent command relating to file access will act upon the SD card. Try this by typing FILES to confirm that you can indeed see any files stored on the SD card (see Fig.11). Note that DRIVE “A:” will switch back to the Flash drive, but for now let’s leave it pointing to the SD card. The COPY B2A command Now let’s demonstrate one example of how we can use the new Flash drive storage feature. Typically, if we want to display an image file on the TFT display, we would use the LOAD IMAGE “filename$” command. This would then read the image from the SD card (with the relevant filename) and load it onto the display. However, this means that the SD card (containing the image file) must be inserted whenever we want to load the image to the screen. A possible alternative that we now have is to store the image file in the Flash drive, and use the LOAD IMAGE command to load the image file from there instead. This means that the SD card no longer needs to be present (apart from the initial copying of the image file from the SD card into the Flash drive). Let’ work through the steps to demonstrate this; noting that along the way we will be using another new command: COPY B2A. 1. Begin by downloading a copy of the sample image file (Welcome1.bmp) from the March 2023 page of the PE website (see above). This image is shown in Fig.12; it is what will be displayed on power-up of the completed fingerprint reader. 2. Copy the Welcome1.bmp file onto an SD card. Practical Electronics | March | 2023 3. Insert the SD card into the socket on the Waveshare display module; then check the file can be seen by typing the FILES command. This should reference the B: drive – if not, type DRIVE “B:” followed by FILES. 4. To copy the image file from the SD card into the Flash drive, enter the command COPY B2A “Welcome1. bmp” TO “Image1.bmp” 5. Switch to the Flash drive by typing DRIVE “A:” 6. Now type FILES to check that the image file is now in the Flash drive (see Fig.13). Note that we renamed the file Image1.bmp when we used the COPY B2A command in step 4. 7. Remove the SD card from the socket. 8. With the PicoMite still referencing Drive A, type the command LOAD IMAGE “Image1.bmp” and it will appear on the display. The above is just one example of how we can use the built-in Flash drive (instead of an SD card) to store files – in this case, just a single image file. Likewise, we could store some sound files onto the Flash drive (copied initially from an SD card like we did in step 4 above). The PicoMite’s program-code could then trigger the relevant sound file as appropriate without the need for an SD socket in the final circuit build (useful if making a large quantity of a particular product). Now consider the Pico expander Module we assembled above. This has a PicoMite installed, and a separate display module that includes an onboard SD socket. The arrangement of these two makes a great configuration platform because we can use it to copy any required files from the SD card into the PicoMite’s Flash drive. Once this is done, the PicoMite can be removed and replaced with another one. Then, by repeating the C O P Y B 2 A process, the second PicoMite’s Flash drive can be loaded with the required files. Repeating this process allows a lot of PicoMites to be configured quickly without the expense of an SD socket in the final project build. For anyone interested in the other available commands and features regarding the Flash drive, I recommend referring to the latest version of the User Manual. Waveshare display module, there is nothing really to test since it is simply a plug-in module. During the configuration performed above, the command GUI TEST LCDPANEL provided a suitable test to ensure it was working. Likewise, the DRIVE “B:” command followed by the FILES command checked that the SD-socket was working. However, the R503 fingerprint module, and the RTC module are connected via DuPont leads – so let us now work through the steps to check these. R503 test To check the R503 fingerprint module, we enter a short test program. Type EDIT to launch the Editor, and then enter the following five-line program: SETPIN GP2,DIN DO PRINT PIN(GP2) PAUSE 100 LOOP Referring to Fig.9, you will see that GP2 is connected to the R503 ‘Finger Detect’ output signal. In the above program, GP2 is set as a digital input (DIN), and then a continuous LOOP prints the logic level present on this pin (with a delay of 100ms between each ‘sample’). With no finger present, the value 1 should be returned; and when a finger is detected on the R503 sensor, the value 0 should be returned. Now test that this is indeed the case. If not, check the 3.3V power connection to the R503, and also check the connection to GP2. If it is still not working, it is worth removing the Finger Detect signal from GP2, and then with the program Hardware test Having assembled the Fingerprint Reader hardware on a Pico Expander module, we just need to confirm that everything is Fig.13. The COPY B2A command is used to copy connected correctly. For the files from the SD card to the Flash drive. 53 still running, use a wire between GP0 and 0V to check it shows a returned value of 0. Likewise, short GP2 to 3.3V and check it shows a value of 1. To check the Tx and Rx pins, download the test program file R503ComTest.txt from the March 2023 page of the PE website (go to: https://bit.ly/pe-downloads) and load it into the PicoMite. Type RUN to launch the test, which will turn on the ring LED with a blue colour. If this is not observed, check the Tx and Rx signals, and switch them over if needed. With everything connected correctly, the LED will be lit blue, and that completes the R503 checks. to + and –), and the two I 2C connections going to pins GP20 (D) and GP21 (C). Also check the OPTION SYSTEM I2C parameters are GP20 and GP21 (use OPTION LIST to do this). Once the time is set in the RTC, power down the PicoMite, and after a few seconds, reapply power. Now type RTC GETTIME to load the RTC’s maintained date and time into the built-in system variables DATE$ and TIME$. With this done, type PRINT DATE$ followed by PRINT TIME$ to check that the correct date and time are displayed. If they are showing correctly then this test is complete. However, if the time is showing 00 for hours and minutes (and the true time is not just after midnight!) then there is an issue, as the time has not been maintained by the RTC. I have only ever experienced this on one occasion and that turned out to be a faulty RTC backup battery. RTC test Next time The first step involves setting the date and time in the RTC module with the RTC SETIME yy,mm,dd,hh,mm,ss command. Use a suitably accurate time source such as an internet-based clock (https://time.is/GMT) and replace the parameters shown with the appropriate values. For example, if it is currently 8:36:45PM on 16 February 2023, round up to the next whole minute (or two minutes if more appropriate) and at the command prompt, enter the command as: RTC SETTIME 23,02,16,20,37,00 If an error is displayed that states ‘RTC not found’, then carefully check the four wires connecting the RTC to the PicoMite. There are two power connections (3.3V supply Next month, we’ll finish the Fingerprint Reader with a brief description of the software that we’ll be making available. Plus, we’ll begin the discussion of our next project, which is based around the popular ESP32 Wi-Fi module. Until then, stay safe, and have FUN! Micromite code The code in this article is available for download from the October 2022 page of the PE website. GET T LATES HE T CO OF OU PY R TEACH -IN SE RIES AVAILA BL NOW! E Questions? Please email Phil at: contactus<at>micromite.org Order direct from Electron Publishing PRICE £8.99 (includes P&P to UK if ordered direct from us) EE FR -ROM CD ELECTRONICS TEACH-IN 9 £8.99 FROM THE PUBLISHERS OF GET TESTING! Electronic test equipment and measuring techniques, plus eight projects to build FREE CD-ROM TWO TEACH -INs FOR THE PRICE OF ONE • Multimeters and a multimeter checker • Oscilloscopes plus a scope calibrator • AC Millivoltmeters with a range extender • Digital measurements plus a logic probe • Frequency measurements and a signal generator • Component measurements plus a semiconductor junction tester PIC n’ Mix Including Practical Digital Signal Processing PLUS... YOUR GUIDE TO THE BBC MICROBIT Teach-In 9 – Get Testing! Teach-In 9 A LOW-COST ARM-BASED SINGLE-BOARD COMPUTER Get Testing Three Microchip PICkit 4 Debugger Guides Files for: PIC n’ Mix PLUS Teach-In 2 -Using PIC Microcontrollers. In PDF format This series of articles provides a broad-based introduction to choosing and using a wide range of test gear, how to get the best out of each item and the pitfalls to avoid. It provides hints and tips on using, and – just as importantly – interpreting the results that you get. The series deals with familiar test gear as well as equipment designed for more specialised applications. The articles have been designed to have the broadest possible appeal and are applicable to all branches of electronics. The series crosses the boundaries of analogue and digital electronics with applications that span the full range of electronics – from a single-stage transistor amplifier to the most sophisticated microcontroller system. There really is something for everyone! 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