Tony is a Geek

A previously mentioned, I have purchased pre-assembled Z80-MBC3 and RC2014 electronics boards and components, waiting for "that" rainy day to come along.... Well, yesterday was that day, and boy did it rain!  Today, however, lovely sunshine and blue skies.  It's early and I'm killing time until I can go and pick up my Jaguar STR, after she's had some bodywork repairs done by an expert/professional.  Don't know what one of those is? click here. very rare actually, they only made 129 in the '07 year and there is probably about 30 left on the road.  As the paperwork says, "it was the fastest production road car when it was released.  faster than any supercars out there...", food for thought, huh? anyway, side-tracked. So, I have a couple of Z80 CPU based computers I'm going to build - except, they are new, but they are old, retro-vintage, if you like.  What's a Z80, you ask? (then you must be <40yrs old), here you go: Basically, without ...

Following on from my previous post about PICO, VGA and using the PICO DEMO board .... I had concluded that I was able to use the pico demo board to get a VGA output - awesome! I had concluded that I was able to build the MCUME emulator code and that it was failing to read the SDCard.....with a "Card not ready yet" error message (3). As I'm a stubborn old-git, I refused to let something like a simple error message prevent me from proceeding. I tried a few more things, even use a bit of MicroPython in an attempt to read the card - that failed too. However, I then noticed on the website for the product that it states: Please note that VGA Demo Base only currently works with the C/C++ Pico SDK! At which point I did a Homer Simpson and face-palmed my forehead. Okay, time to get blowing off the C code cobwebs properly then.... I then tried a few variants of other people C code and found that didn't work either. I kept coming back to the PIN diagram: and the reference from...

Okay, not that one.... How am I only finding out about this now? Yes, you can opt. for MicroPython, if that's your thing... and there are lots of "extra" IoT components that you can add too. I added the SDCard and ILI9341 components to the screen above - you can then link them up to the GPIO pins. You can then write the C code, as you would normally.... and then you can execute the code and DEBUG it normally. This is quite an interesting concept - I am not sure exactly how many times you can re-flash the actual PICO, but it will have a shelf life... and I reckon over the past 2 weeks, I've probably flashed mine about 500 times!  Obviously, this won't replace the need for actual device testing - but, it will help reduce the code / test / debug / get it right cycle and then once happy then extract out. Yes, it also won't cater for custom hardware either - but I do believe it does allow you to upload your existing code / libraries and will include them - I need t...

Right, I've done enough of the MicroPython stuff now.... let's get back into my comfort zone.... let's go back to the 1990s and write some C code 🤓  Okay, C code isn't specific to the 1990s, but it is when I was first introduced to it....(actually it may have been 1989, but who's nit-picking) and I've been using it on the Arduino for a few decades now.  So it makes sense to now remove the training wheels with the PICO and get back to the lower-level.  As I'm wanting to do stuff with the VGA screen output, it makes sense to go down a layer (I'm keeping above the ASM waterline for now!) The image above actually comes from THIS webpage, however, I didn't follow those instructions, I did however learn something new...scrolling down the article, the nice chap let's us know that GPIO Pin 30 is a RUN pin and if you flip it then it does a hard-reset - this saves you having to unplug the USB cable and plug it back in every time you want to reset - that...