PIC'ing the chips :)

Well, PIC migration has started in earnest now…

 

Following a few setbacks…..

Bit of a pain when the programmer you have is no longer supported.

More of a pain when the new programmer doesn’t have one of the useful features of the old one – I’ve moved to Pickit3 programmer from Pickit2. The only drawback I’m finding is that the Pickit3 programmer does not seem to have the capability to act as a serial communication interface – by which I mean with the Pickit2 (and picaxe cables) you could use them to communicate with a terminal program on the PC so you could see the results of serial output, or simulate a serial input – which was rather useful.. actually.. fairly critical in being able to get the serial communication part of the Arcturus signal working. It’s also useful in seeing what is being sent to the audio modules to ensure the correct commands are being sent.

I can’t do that with the Pickit3.

Bugger.

I CAN get a usb-serial interface doohickey that will let me do that and that should be arriving tomorrow all being well. Even though it’ll mean an extra thing cluttering the workbench – But that’s a definite 1^st world problem 😊

Once that arrive I’ll be able to figure out what I’m doing wrong with the serial signal at the moment and get it sorted. Then after that all I need to do is internally modulate the signal and the hardware side of the migration is sorted – It’s just a case of writing the code to slot it all into.

YAY 😊

 

HOWEVER…. Yeah.. There is always a however ain’t there 😊

 

What I CAN’T do (at least for the emitter circuits) is a pin for pin replacement of Picaxe for Pic.

Why? Well, it seems that for some of the functions of the processor, rather than using the hardware modules on the underlying Pic, the Picaxe uses software equivalents.

For example: Interrupts

Interrupts are useful little things that enable you to tell the processor that something has happened and to well.. interrupt what it’s doing and deal with it. This is useful for things like detecting button presses or incoming signals (Y’know… nothing much.. just something that makes up most of what I want 😊 ).

Now, the Picaxe 14M2 chip I use has external interrupts (for button presses) available on pins 5,6 & 7. The underlying Pic chip (16F1825) has external interrupts on PortA – that is, pins 2,3,4,11,12 & 13 – While this is handy as I need more interrupts, it’s a pita – not a HUGE pita as it’s a  minor change going forwards. The biggest problem is the sensors – Luckily the interrupts on the pic used in the sensors are fine – the possible issue with those is the signal input/reading may need to change pin. Handily though if that’s the case, the sensors boards are modular so it’s not too much to change them out (at the cost of some Veroboard, couple resistors, IC chip socket and some soldering).

It’s a similar case with the serial comms, the Picaxe has it on a number of the pins, but the Pic there are a choice of 2 pins – and one of those is the one that will output the modulated signal so that narrows it down even more. The Picaxe has a dedicated command to output/input via the same pin as the Pic.

 

Still. Things are coming along steadily, and given that the Picaxe chips were initially intended as a teaching/learning tool, they have certainly done that, as if I’d have gone straight into the Pic development, I wouldn’t have known where to even begin so in that respect they have been perfect.

 

But it’s time to move on.

Mind you, it also helps that the Pic chips are slightly less than half the price of the Picaxe based on them 😊