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1. 

   jessb
   LeafLabs

   We're working on moving the RET6 boards out of beta, and there are a couple of different options we've been discussing in the office. If any of you have thoughts/feedback/must-haves, we'd love to hear it.

   So, first, there are 5 pins we'd like to have broken out that aren't currently:
   1) BOOT0 (so it can be toggled from shields)
   2) PA11 (currently USBDM, has CAN lines)
   3) PA12 (currently USBDP, has CAN lines)
   4) PC11 (curently USB_P, has UART4_RX and SDIO_D3)
   5) PC12 (currently DISC, has UART5_TC and SDIO_CK)

   It's going to be difficult to fit all these lines onto the current Maple. So here are a couple of options, please weigh in as to what you'd prefer.

   1) only break out two of these lines, to be fitted right below where pins 22 and 21 are currently. Would fit pretty neatly; if you prefer this option let me know which two lines you'd want broken out.
   2) try to somehow jam header spaces for all five of these lines somewhere in the current design. If you want this, lemme know how you'd like it to all fit together, because I can't come up with a good scheme.
   3) Extend the board very slightly (about .2 inches?) so that that mounting holes match up with the Arduino Uno. Would probably give us room to add one more pin each on the ends of the top left and bottom left headers (next to where pins 14 and RST are). Two more pins would go as described in option 1. Cons, it's kind of awkward to add just one pin here and there, numbering scheme would be weird or would have to be changed, etc.
   4) Extend the board a lot so the entire form factor matches Arduino Uno. We could then likely fit all the desired pins in the top left corner, where Arduino Uno reads "Made in Italy" right now. We could populate this header or not. Pros, Arduino shields would fit better because the barrel jack wouldn't get in the way any more, plenty of space. Cons, Maple would be bigger.
   5. Something else entirely?

   We are also planning on switching the JTAG header to the Cortex Debug Connector, and breaking apart the reset and jtag-reset lines.

   What do you guys think?

   Posted 4 years ago #
2. 

   mbolivar
   LeafLabs

   Just for everybody's reference, here are pointers to the Maple RET6 Edition's errata that these would fix.

   4) PC11 (curently USB_P, has UART4_RX and SDIO_D3)
   5) PC12 (currently DISC, has UART5_TC and SDIO_CK)

   Fixes:

   http://leaflabs.com/docs/hardware/maple.html#maple-ret6-uarts
   http://leaflabs.com/docs/hardware/maple.html#maple-ret6-sdio

   We are also planning on [...] breaking apart the reset and jtag-reset lines.

   Fixes:
   http://leaflabs.com/docs/hardware/maple.html#maple-nrst-pb4

   Posted 4 years ago #
3. 

   robodude666
   Member

   I've been wanting to comment on the Maple's design and pinout for a while so this seems like the perfect time.

   The Maple is very special. It's not a beginner's toy. The STM32 packs a lot of punch into a very small package, and combined with libmaple you can do some very powerful stuff. Limiting the Maple's design to fit the Arduino formfactor, a formfactor based on an 8-bit MCU with a fraction of the GPIOs and functionality, is silly. I know that's what the Maple Native aims to do, but I honestly think all Maple boards shouldn't be limited by this design.

   The Maple Mini is a great step up from the Maple's original design. There are some changes in the design that I really like. For instance, every pin is brought out (okay, except for PB9 aka "DISC" and PB1 aka "blinky LED".. ahem!). Also, Vbat is no longer tied to Vin, allowing a coin-cell battery be used for the RTC. And while the pins aren't all contiguous in pinout, most of PORTA stays together which is great.

   Okay, so I don't know the first thing about routing a board efficiently. I hit Autoroute and hope it works out, so I understand why the ports are brought out the way they are. However, I really dislike the fact that you need to reference multiple documents just to figure out where multiple contiguous pins are located. Okay -- so maybe not everyone is using devices that requires a parallel interface, but it's still nice to know where things are if you're not using wirish.

   Personally, I really like what StackFoundry has done with their Megavore. It's based on ATMEL's ATXMega128A1 so, like the STM32F103xxx chips, it too has more GPIOA and functionality than a standard Arduino's ATMega. It maintained an arduino-compatible pinout but it also brought out all of the pins in a single port together -- you know, PA0-7 on a single header, PB0-7 on a single header, etc. I would love to see something similar, possibly. Would be great to see all of PORTA0-15, PORTB0-15, PORTC0-15, etc. brought out. I also know the STM32F103RET6 comes in a 100-pin package that has 51 GPIO vs the ~30ish the 64-pin package has. Would be great to see them all too, though that's a drastic redesign.

   Some other things I'd like to see in a redesign would be a power selection switch. The jumper headers are great, and Arduino used them too at the beginning, but that block takes up a lot of space. It would be nice to see a 3-way selection switch for the power source, a on/off switch for the charger, and a master on/off switch (so the battery could remain connected, for example, with the Maple powered off).

   I can ramble on, but I'll stop here for now.

   -robodude666

   Posted 4 years ago #
4. 

   mbolivar
   LeafLabs

   robodude666,

   However, I really dislike the fact that you need to reference multiple documents just to figure out where multiple contiguous pins are located.

   "Multiple documents"?

   http://leaflabs.com/docs/hardware/maple.html#master-pin-map

   Posted 4 years ago #
5. 

   robodude666
   Member

   I refer to that list (in the board header file though), in addition to the schematic, and a similar list I made sorted by GPIOx instead of Dx. I found going by just that list alone is slightly annoying since some of the pins are scattered around.

   However, by now I've been working with my Maple for a few weeks and have the pinout memorized more or less, so it's not as big of a deal as it was when just starting out. I can probably retract that statement altogether, honestly.

   Posted 4 years ago #
6. 

   mbolivar
   LeafLabs

   robodude666,

   Okay, fair enough:

   https://github.com/leaflabs/libmaple/commit/c092b10afb3620dc739646c9dca5fcf41c5f6084

   Posted 4 years ago #
7. 

   gbulmer
   Moderator

   Do you mean, the 0.1" pitch, or the 0.05" pitch Cortex debug connector?

   I'd rather see Oak. IMHO Oak is a much more interesting device than a reworked Maple.

   Posted 4 years ago #
8. 

   jessb
   LeafLabs

   robodude, thanks for such a considered reply. I can see where you're coming from on the pin mappings; however on Maple the pin order probably won't change much in the future in order to preserve back-compatibility. Maple Native is designed to take the functionality of the chip into consideration a little better, by grouping ports and peripherals together in a way that's informed by the chip itself, rather than the desire to emulate Arduino.

   You're right that the power scheme is pretty non-optimal. We're trying to come up with something a little cleaner for use in the future. We've been playing with auto-selecting power schemes but running into issues; a three-way switch might be a good middle ground.

   gbulmber, the 0.05" pitch one (here: http://www.samtec.com/ftppub/pdf/ftsh_mt.pdf). I'd rather see Oak too, honestly. We've been working on it, but you've got to have side projects during that interminable gray purgatory of waiting on spins...!

   Posted 4 years ago #
9. 

   Darth Maker
   Member

   I'd just like to say that one of my favorite things about the Maple is it's size. The Uno is too big if you ask me, and it has less I/O to boot.

   I would be difficult to work the silkscreen around, but the extra pins to be set beside the current digital pins, similar to how the chipKIT boards are.

   I don't actually plan on getting a RET6 Maple, so my opinion isn't really that important on this one, but if only two pins are broken out, I would choose the two UART pins. You can always use another UART, especially since software serial hasn't been converted yet.

   Posted 4 years ago #
10. 

    smartroad
    Member

    I have been thinking about using Maple for a project where I could use the extra horsepower compared to my Arduino.

    In terms of form factor, I like the idea of keeping it within the Arduino footprint/layout, with all the shields out there it is useful for prototyping. I did think about an "extended Arduino" form factor where the additional pins are just outside the existing pins. That way you maintain compatability but also allow for extended shields if you wanted; and even with a shield in place, you can access the new pins anyway.

    Just my thoughts :)

    Posted 4 years ago #

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