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Hot!PIC32MM or PIC32MX: Is anybody actually using the MM?

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JPortici
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2019/12/09 09:36:06 (permalink)
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PIC32MM or PIC32MX: Is anybody actually using the MM?

I have a small device in mind that will use either HID usb or a vendor configuration (just an in/out bulk endpoint). Given the other requirements in order of peripherals and performance both 32MX and 32MM should work, and i already have a PIC32MX board laying around that i can use to develop the code, but i also have some 32MM laying around to use "just in case"
 
I wonder if i should give the MM a try.
I wonder if anybody is actually using them, and why instead of a MX or other architectures at all. Crystal-less usb is a nice feature but besides that i can't see much appeal
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    NorthGuy
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/09 09:46:12 (permalink)
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    MMs have micromips - more code will fit into the same space. They have shadow registers, thus better interrupt latency. They don't have cache and are said to be cycle-accurate. They also have new periphery, such as CLC.
     
    I haven't used them for real projects, only for testing.
    #2
    jg_ee
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/09 09:48:27 (permalink)
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    The two main selling points are the cost of the chips (2-3x cheaper), as well as supposedly lower power consumption with their XLP tech.  I have not actually compared power versus operating conditions myself though.
    #3
    JPortici
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/09 10:00:18 (permalink)
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    (To be honest, i would just use a dsPIC of the MU series if they didn't cost five times as much, most of the code is already written)
     
    I would still be curious in seeing sales data and know if they have plans to keep updating the line, because even though cost is really low the current revision still has at least one showstopper: missing codes for the ADC in 12bit mode. I do not need the ADC in this particular application, but if i'm hesitant to start building a codebase because if i need an external ADC i'd rather just use a different chip.
    #4
    Jim Nickerson
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/09 10:40:49 (permalink)
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    I use the MM and like it, it is much smaller and still uses xc32 like my MX
    #5
    acharnley
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/09 16:07:46 (permalink)
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    I'm using the MM for my next product. It is a good question, but I may have an answer for the 64 pin version - nobody :) - the reason being is I discovered the footprint pad is completely wrong in the datasheet (won't reflow) and I'm the first person to have reported it.

    You can only use crystal-less USB in device mode (not host). Something to bare in mind.

    Personally I think the MM is seriously good value, you get 4x CLC's, PWM's without the FOSC/4 restriction of PIC16/18, interrupt priorities (PIC18 can do this I believe), an extra comparator over the 16/18, plus a lot more speed and memory for a few extra cents. IMO it's Microchip's best value chip.
    #6
    acharnley
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/09 16:10:16 (permalink)
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    Jack_M
    (To be honest, i would just use a dsPIC of the MU series if they didn't cost five times as much, most of the code is already written)
     
    I would still be curious in seeing sales data and know if they have plans to keep updating the line, because even though cost is really low the current revision still has at least one showstopper: missing codes for the ADC in 12bit mode. I do not need the ADC in this particular application, but if i'm hesitant to start building a codebase because if i need an external ADC i'd rather just use a different chip.



    Missing codes, can you elaborate?
    #7
    JPortici
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/10 01:43:04 (permalink)
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    You haven't read the errata, have you? always read the errata.
    http://ww1.microchip.com/downloads/en/DeviceDoc/PIC32MM0256GPM064-Family-Silicon-Errata-and-Data-Sheet-Clarification-DS80000729E.pdf
     
    Why it can be crystal-less only in device mode is pretty obvious, besides it's clearly written on the first page (yes i saw you missed it there!) and in the oscillator chapter.
    #8
    JPortici
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/10 01:43:32 (permalink)
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    In the meantime, i found a SSOP-DIP adapter so i'm cooking up a small board.. let's see where this goes
    #9
    JPortici
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/10 08:44:10 (permalink)
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    Holy shit the PK4 is actually FAST to program and debug the MM. literally one second to erase and program a small USB HID test firmware (about 8k of flash)
     
    I don't remember if i have tried with the PIC32MX but it's not this fast with the MK,MZ or dsPIC
     
    the ICD3 instead has still some annoying issues (way slower to erase/program/debug, goes out of sync, things like that)
    post edited by JPortici - 2019/12/10 08:45:46
    #10
    NorthGuy
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/10 09:00:49 (permalink)
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    Jack_M
    the ICD3 instead has still some annoying issues (way slower to erase/program/debug, goes out of sync, things like that)



    Based on what people posted, ICD3/PICkit3 used to program the whole chip, but ICD4/PICkit4 skip the parts which are not programmed.
    #11
    acharnley
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/10 13:14:21 (permalink)
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    Jack_M
    You haven't read the errata, have you? always read the errata.
    http://ww1.microchip.com/downloads/en/DeviceDoc/PIC32MM0256GPM064-Family-Silicon-Errata-and-Data-Sheet-Clarification-DS80000729E.pdf
     
    Why it can be crystal-less only in device mode is pretty obvious, besides it's clearly written on the first page (yes i saw you missed it there!) and in the oscillator chapter.



    No I don't, and yes I will in the future I'm quite shocked by the amount of errors. I think this one in particular is going to effect the prototype I just ran off. Feck. "The OCM3A output for MCCP3 is not functional."
    #12
    JPortici
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/11 01:30:35 (permalink)
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    Please note that silicon issues are not uncommon and this is true for every single manufacturer. at least microchip puts the info on the product page in plain view.
     
    In the past i have found great difficulty to find erratas for stm chips, just to mention one.
    Or god knows WHAT happens and what changed in the extremely complicated logic inside TI's freaking LDOs in order to have three chip revisions in one year
    #13
    egan.fryazino
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/11 03:50:05 (permalink)
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    pic32mm have microAptiv core: it's support up to 255 interrupt sources, so in pic32mm you will get less pain with interrupt processing(irq and vector number is same number).
     
    pic32mm can start timer0 without external oscillator(it can use lprc), so you can make sleep() backend, that works without external osc.
     
    as already said, pic32mm is cheaper and have xlp.
     
    *pic32mm asm-compatible with pic32mx, so you can easyly make mmport from pic32mx code.
     
    #14
    DominusT
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/11 06:40:16 (permalink)
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    I think that for new projects you have to think about the possibility of migrating to SAM32
    #15
    JPortici
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/11 07:28:31 (permalink)
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    Ah, the third option nobody asked for
    (i was genuinely disgusted by the documentation and unimpressed by the peripherals in the atsam devices i evaluated)
    #16
    DominusT
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/11 07:46:55 (permalink)
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    Jack_M
    Ah, the third option nobody asked for
    (i was genuinely disgusted by the documentation and unimpressed by the peripherals in the atsam devices i evaluated)


    MCHP is putting aside the PIC32 and give more impetus to the SAM32. Even its new development tools have an Atmel device as processor
    #17
    Howard Long
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/11 08:13:28 (permalink)
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    NorthGuy
    Jack_M
    the ICD3 instead has still some annoying issues (way slower to erase/program/debug, goes out of sync, things like that)



    Based on what people posted, ICD3/PICkit3 used to program the whole chip, but ICD4/PICkit4 skip the parts which are not programmed.




    IME it depends on the PIC sub family, and how smart the Microchip employee felt like being on the day. On some devices, the entire chip seems to be programmed, whereas on other it's just what's needed.
     
    It's a bit of a hare vs tortoise phenomenon: do you take the apparently quick but bleeding edge ICD4/PICkit4, or the slow but sure ICD3/PK3.
     
    On the instances where ICD3/PK3 is slow because it unnecessarily programs the entire flash, you can always manually set the upper flash limit if you get a bit impatient.
    #18
    JPortici
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/11 09:26:57 (permalink)
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    True dat, but in the MM debug is still faster, more reactive and more stable when using a Pickit4 versus the ICD3, the same can't be said for any other pic i tried with is
    #19
    friesen
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    Re: PIC32MM or PIC32MX: Is anybody actually using the MM? 2019/12/18 05:13:34 (permalink)
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    Mplabx plus sam looks like it needs a bit more time before it’s ready for the public.

    Erik Friesen
    #20
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