Tag: ff0000

doing a little java work — getting set up

whbeebe
IntelliJ IDEA 2023.3.2 (Community Edition) with a basic boilerplate project it created.

I suddenly find I have need to do a little Java development. It’s been a long time since I dipped my fingers, as it were, into writing Java code. This was back around Java 9 (September 2017) and it was such as mess with the way Oracle had blown up Java’s libraries that I just basically walked away from Java. I still install it when I need it because I have some tools that depend upon the Java runtime.

Here I am trying to come up to speed, which at this point in my life may be impossible. I haven’t changed so much as Java has. Right now I’ve installed Java 21, what now passes for an LTS. I’ve installed the JDK and an IDE to work with it on my M1 Max MacBook Pro. Here’s what I did to get something working.

First I tried to install the JDK. I went searching for the latest LTS that would run on aarch64/arm64. When I searched on Duck Duck Go, I got nothing but hits on installing the Oracle version, which is not what I wanted. Instead I had to remember to search for Adoptium ( https://adoptium.net ). Rather than take the default offered on the landing page I chose to go to the alternate downloads page and pick it that way;

Adoptium Latest Releases page

As you can see I whittled my choices down to two. I went with the .pkg because it’s a Mac, so that should be a no-brainer installation. That was a mistake. It installed alright, I just don’t know where. I came back and downloaded the tar.gz archive, unpacked it in a location in my local folder, defined JAVA_HOME to point to the location and then added it to my path. Once that was all done I could do a java --version and get the LTS version release.

I then decided to install NetBeans 20. I was a long-time NetBeans user and felt comfortable trying it again. The problem is that it would never find my installation of Java. I finally went into the app directory structure and ran, from the command line, ./netbeans --jdkhome $JAVA_HOME, at which point it finally came up. I was able to set up a decent look-and-feel and began to get comfortable with it. I even checked to see if NetBeans knew about the local Java installation, and it appeared to. However, when I closed NetBeans and tried to start it via Launchpad, it failed to start just like before. After that I removed NetBeans and installed IntelliJ IDEA 2023.3.2 (Community Edition) and immediately got to work learning how to get productive with it. I’ve used IntelliJ tools in the past for a number of years and I’ve never been disappointed. This time I chose to use the Community Edition because I didn’t need the full-blown suite, and I don’t have the funds right now to pay for a full commercial license. Maybe if this bit of work leads to something more substantial then I’ll expense it. Right now I’m just getting started.

So far the choices I’ve made appear pretty solid, and IntelliJ IDEA is a very nice environment.

step 1 is complete

whbeebe
ESP32-S3-DevKitC w/MAX2719 and 1088AS LED 8×8 Matrix

The first step in my plan for world conquest having an ESP32-S3-DevKit1 communicate with a MAX7219 is complete. All it took was five wires, two of which supplied power, and a little bit of MicroPython code running on the latest MicroPython release, and I was able to send text to my inexpensive four character matrix display I purchased on Amazon.

ESP32-S3-DevKit1 w/MAX7219

The code depends upon a library I found on GitHub (see links section below). Here’s the test code sample I wrote;

# Enable SPI and clear the display, which turns off all LEDs.#import max7219from machine import Pin, SPIimport timespi = SPI(1, 10000000, sck=Pin(12), mosi=Pin(11))cs = Pin(10, Pin.OUT)display=max7219.Matrix8x8(spi, cs, 4)display.fill(0)display.show()time.sleep_ms(500)# Probe the MicroPython/ESP32-S3-DevKit1 environment.#import gcprint(f"  MEM: {gc.mem_free():,} MB")import espprint(f"FLASH: {esp.flash_size():,} MB")import platformprint(f" PLAT: {platform.platform()}")import osUNAME = os.uname()[-1].split(' ')[-1]import binasciiimport machineUNIQUE_ID = binascii.hexlify(machine.unique_id()).decode('ascii').upper()print(f"  UID: {UNIQUE_ID}")SSID = UNAME + '-' + UNIQUE_ID[-4:]print(f" SSID: {SSID}")# Display text on the four 8x8 matrix displays.#display.text(UNIQUE_ID[-4:],0,0,1)display.show()

I’m using Thonny 4.1.4 to program the ESP32-S3. Here’s the output from boot.py in Thonny’s console when it’s run;

  MEM: 8,310,688 MBFLASH: 8,388,608 MB PLAT: MicroPython-1.22.1-xtensa-IDFv5.0.4-with-newlib4.1.0  UID: 7CDFA1E3C534 SSID: ESP32S3-C534

The four characters on the 8×8 displays are the last four characters of the UID. It’s a better “proof of life” than something random. To get the code listing to run, you need to download the single GitHub file from the link below, move it onto the ESP32-S3 controller, and then import it to begin to use the 1088AS displays.

Step 2 is to get Bluetooth operational on the ESP32-S3.

Links

MicroPython MAX7219 8×8 LED Matrix library — https://github.com/mcauser/micropython-max7219

designing the esp32-s3/max7219 device