Dont be silly. Ben Eater, Mitxela, BigClive?

True, I thought I explained that. Sorry if it wasn't clear.

I think you missed the point, not the creator

Glad you think so!

On any board using the RP2040

Not ragging on the Pico at all - but interfaces like these have been available on many MCUs for years. For example the Teensy 4 has it, many STM chips have it, etc. That said, I am glad to see it becoming more mainstream through the Pico, it's a powerful combo between MCUs and FPGAs that I've been anticipating for years. Hopefully they will release another version of the Pico in a BGA package with a lot more IO pins. And native USB 2.0. Then it would be useful for something more sophisticated than hobby projects.

@@yum33333 I am familiar with the Teensy 4 and 4.1, but the 3x FlexIO interfaces (loosely PIO equivalents) on those are quite different in philosophy. The Pico's PIO instructions all execute within 1 cycle and have multiple functions going on at the same time in the same instruction. For example, writing out of the Output Shift Register (OUT instruction) can additionally shift the bits at the same time as well as adding delays (if desired). Each PIO command is highly code and execution efficient and can run at the same frequency as the ARM core itself. The PIO state machines effectively allow certain limited parallel operations to occur, often faster than even a dedicated ARM core itself could. On the other hand, Teensy's FlexIO is limited to 120MHz, which on a 600MHz Teensy 4.1 makes it less useful, as in it is really only intended to offload deterministic bit-banging operations from the ARM core. It does not execute instructions faster than the ARM core itself. This difference in the Pico's PIO philosophy has made projects, like a logic analyzer using the PICO operating with 21 digital channels with up to 120 MHz capture speed (hackaday.com/2022/03/02/need-a-logic-analyzer-use-your-pico/) possible. A 120MHz logic analyzer run on a humble device costing just $4 is quite an achievement and illustrative of the difference in PIO philosophy.

@@yum33333 Which STM chips have PIO functionality like this? Got an example part number? I came across something similar in the LPC4300 many years ago but not so far met it in STM.

@Mark Warburton "revolutionary"...? HAHAHA. Parallax Propeller, two-fucking-thousand-six. en.wikipedia.org/wiki/Parallax_Propeller

@@AttilaAsztalos That Parallax Propeller is an eight core MCU that is at least an order of magnitude more expensive, even now, compared to the RP2040. The reason is it has 8 fully functional cores that are more similar to the dual ARM cores in the Pico than to the PIO. The Pico's "revolutionary" approach is to offer multiple PIO state machines running at the same frequency as the ARM cores and taking up very little die space to achieve that, so keeping costs down.

Section 3.6.1 of the RP2040 datasheet shows you how to do full duplex SPI. Also section 3.2.7 covers Interactions Between State Machines, where it says, "State machines can not communicate data, but they can synchronise with one another by using the IRQ flags."

@@GaryExplains Oh, neat. Thanks for the reference.

@@trevorschrock8259 Also, it is possible to configure DMA to feed (empty) the FIFO and, again, offload the main processor.

Yes

@@GaryExplains Great, Thanks for the quick response.

Well of course rx and tx are relative to which side you are on. But they do have defined names, so sorry if I confused them.

@@GaryExplains plz tell about ur other chanel speed test g???

I don't think a wrap is actually a jump. At the end of the code, the PC for the next instruction is set to the wrap target rather than PC+1.

I don't know if it is supported by mmbasic, I guess it would be best to ask the mmbasic people.

Yes, out_base defines the start pin, so if say gpio16 is set as the base, pins greater than that can be used. Also, look at the use of the .side() option on commands which can also be used to control additional pins.

The Raspberry Pi people already did that here: github.com/raspberrypi/pico-examples/blob/master/pio/i2c/i2c.pio

@@GaryExplains thanks for the reply I've seen this code it's in c but I wanted to do in micropython

I also wanted my pico to be used as a I2C slave

OK, so it isn't in C, it is in PIO assembly language, all you need do is convert those to the equivalent Micropython calls or even just use .exec(). Lots of examples here : github.com/raspberrypi/pico-micropython-examples/tree/master/pio

@@GaryExplains thanks for the help Gary

Sadly I have no idea, it is just a stock photo.

That is a good question. Looking at the source code it seems that the activate() function just sets a bit in the CTRL register. The documentation says, "When disabled, a state machine will cease executing instructions" which implies that it stops on the next cycle (I guess). So I think that means that you can stop it with the LED on.

Yes, the PIO can access multiple pins.

Is a state machine when you create a define a function?

🤣

The Pico can be programmed in C as well. So with the Pico you get the option of Python or C and it costs just $4.

@@GaryExplains cool

@@GaryExplains So the microcontrolers can be programmed in C or the main pricoessor?

The Cortex-M0+ processors (there are two of them) can be programmed in C or Python. The PIO have their own special assembly language as I explain in this video. That special language can be loaded into the PIOs from C or Python.

@@GaryExplains Two ARM processors plus another 8 micros. The 8 are assembly and the two are C or Python. I saw the video on the dual core programing. Is there shared resources?

You can use C instead, the principals are the same.

@@GaryExplains Yes, I know I am about to do it. I was hoping the video would give me a head start, but I did not get that much useful from it. No real explanation of "pins", still not sure how that works... how does it compete with GPIO, does it have some form of mask, Interaction with ISRs?. The PIO compiler in the SDK is not shown as you went the python route.I will go and read the data now, but it is a bit of shame as the title of video got my hopes up but I came away having felt I learnt little other "The PIO has 8 programmable units"

Well, I am sorry to hear that, but of course you understand that I didn't contact you before I made the video and asked you what you wanted. I made a different video and plenty of people seem to have found it useful, sorry you didn't. All the information you need is in the datasheet which I link to in the description.

@@GaryExplains To be fair you videos are well made with good presentation, but had you added the word "python" to the title I would have ignored it and saved myself some time.

There's more 'boilerplate' in the typical C version of things: the 'in-line assembler' in Python is more 'terse', so why not go ahead with it here, because the theme here is the PIOs themselves (quite well treated, I think). There was basically no support from the main processor(s) in these examples, except a little poke and peek to the queue depth. To get properly into this you would probably need interrupts and DMA and all that jazz, which would be much more likely well done in C, alas. Gary's series on a muti-tasking OS for the Pico has been quite hot on the low level, though.