Source/Vendor/Part # of Maple "External" 18 pin 10.5 mm female stacking header?

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Source/Vendor/Part # of Maple "External" 18 pin 10.5 mm female stacking header?

(67 posts) (6 voices)

Started 5 years ago by leaflabsandy
Latest reply from gbulmer

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leaflabsandy
Member

The Poslathian Translation:

#1. The external connection is moved "south" (not north) by 0.50" to make it "on grid"

#2. The external connector becomes a 16 pin header connector from a 18 pin connector.

#3. The "pins" on the external connector will be counting from the bottom right to left
and up --> 1(D23) 2(D24) to 15(D37) 16(D38). There would be on grid pads somewhere to accommodate D21 & D22.

#4. D38 (pin 16) will not be ground anymore but the repeat of "the button" tac switch.

----------------------------------------------------------------------------------------

Summary:

#1. Brings the external header connector "on grid" so users can construct protoboards stacking
shields on a even grid of 0.10 ".

#2. Parts for the stacking header can be now easily obtained. The same 8 pin 10.5 mm stacking
header used on two of the other Maple's headers can now be used on the external stacking
header. (You need to double them up)

#3. All of the present Maple's I/O will be preserved.

#4. D38 (Ground) now becomes the repeat of the on board tac switch called "the button".
This allows stacking shields to have both the reset and "the button" tac switch "repeated"
A person could, on his/her shield repeat (in parallel <to ground>) the reset and "the button"
functions with a heaver and larger tac switch(s).
----------------------------------------------------------------------------------------

Is my Poslathian translation correct?

Posted 5 years ago #
gbulmer
Moderator

llAndy, I think #3 of the summary is a bit misleading:

Summary:

#1. ...

#2. ...

#3. All of the present Maple's I/O will be preserved.

Two of the current Maple I/O's are moving to pads on the board (21 AKA. P$2 and 22 AKA. P$3), the rest of the Maple I/O's are preserved on their current headers.
(are P$2 and P$3 are on the 0.1" grid?)
[Santa, would pleeeease move P$3 and P$4 off the header instead of P$2 and P$3? I promise I'll be good next year :-]

#4. D38 (Ground) now becomes the repeat of the on board tac switch called "the button".
This allows stacking shields to have both the reset and "the button" tac switch "repeated"
A person could, on his/her shield repeat (in parallel <to ground>) the reset and "the button"
functions with a heaver and larger tac switch(s).

This is not what I understand from Poslathian's most recent post, so I'd find it helpful if this were clear.

Posted 5 years ago #
leaflabsandy
Member

Quote: #3. "All of the present Maple's I/O will be preserved."

I meant none will be taken away. All I/O will be accessable.

Quote from poslathian above:

"Also to be clearer about the pin 38 issue. Pin 38 IS connected to pc9/the button. The issue is that this pin is not exposed on any header. You can still use pin 38 in your sketches to read from the button.
This is being changed on the silk to reflect that BUTTON=38"

Reply: I think he means D38 or the present pin 18/pc9 of the external header connector?

Posted 5 years ago #
leaflabsandy
Member

Also from the Maple Docs: Errata

Silkscreen errors:
"the external header GND pin as number 38 (actually 38 is connected to the BUT button).
We manually sharpied over both of these mistakes."

Funny .. On the rev 3 Maple schematic pin 38 shows it as a ground!
On the rev 3 Maple board layout pin 38 shows a physical ground.

Funny .. I measured a hard ground on pin 38 with my multimeter?

There must be different versions of rev 3 Maples or the documentation keeper at
Leaflabs must be way behind in his corrections and website docs.

----------------------------------------------------------------------------------------
Another comment - why would anyone use a tac switch directly to Vcc is beyond me.
You see, if a user would somehow force this pin low and press the tac switch it
would short VCC to ground! This could take out the BUT tac switch and the I/O pin.
That is why most professional electrical design engineers put a current limit resistor
in series to prevent this from happening!

So looking back on my previous statement, the reset tac switch when pressed goes to ground and the BUT tac switch goes to VCC when pressed.

Too bad BOTH of them could not be made the same. Repeating both of them, on the headers
would be less ackward. <---- If Leaflabs would allow this to happen?
----------------------------------------------------------------------------------------

Poslathian ... I need a translator!

Questions:

#1. Is D38/PC9/Hdr pin 18/ grounded or not on Maple Rev 3?

#2. Is D38/PC9/HDR pin 18/ connected NOW on the Maple Rev 3 to the on board "BUT" tac switch?

#3. Why are there so much confusion on the website's docs?

--------------------------------------------------------------------------------------
If Leaflabs doesn't allow a header connection to the BUT tac switch then fat finger
people like me could never stack any shields on the Maple because our pinky cannot
reach the BUT tac switch.
--------------------------------------------------------------------------------------

Posted 5 years ago #
gbulmer
Moderator

Reply: I think he means D38 or the present pin 18/pc9 of the external header connector?

Based only on the Eagle CAD, these are the things I believe to be true for Maple rev3:
PC9 is on the STM32F103Rx at pin number P$40.
PC9 is NOT currently connected to any pin on the EXT header.
EXT Header pin 18 is currently connected to Ground.

PC9 (P$40) is connected to BOOT0 (P$60), which is pulled down to ground because that means, by default, the STM32F103 will boot from the Maple USB boot loader, and not the manufacturer-installed serial boot loader.
NRST is asserted low, so it must be held high, and the button pull it low to reset the chip.
It'd take an inverter to make the sense of the two buttons match.

PC9 is D38 in sketches using the Maple headers and libraries.

Posted 5 years ago #
okie
Administrator

gbulmer,
Your answer is correct and very clear.

leaflabsandy,
You're very right on the current limiting resistors! I've added a 1k resistor between reset and GND (for when the RESET button is pressed) and changed R4 to 10k, a 1k resistor between VCC and BOOT0 (for when BUT is pressed), and a 1k resistor between BOOT0 and PC9 in case there's a conflict there.

These are the last changes we'll be able to make on Maple r5. I could not find a clear, easy enough way to route BOOT0 or PC9 to a 0.1" spaced header location.

Posted 5 years ago #
leaflabsandy
Member

Quote: "These are the last changes we'll be able to make on Maple r5. I could not find a clear, easy enough way to route BOOT0 or PC9 to a 0.1" spaced header location."

The "BUT" tac switch is almost hitting D38/GND/HDR18. Remove the ground from D38 then connect to the "BUT" tac switch - very simple.

Posted 5 years ago #
leaflabsandy
Member

As for the current limit resistors the "BUT" needs it because a user could change the
I/O direction from input to output (LOW) and zap the tac and I/O. The reset is always
an input but stacking shields you might need some current protection - be very careful
on the mods for this pin.

Posted 5 years ago #
gbulmer
Moderator

Okie

These are the last changes we'll be able to make on Maple r5. I could not find a clear, easy enough way to route BOOT0 or PC9 to a 0.1" spaced header location.

IMHO, it would have been better to take both RTC oscillator pins (22 and 23, i.e. P$3, PC14/OSC32_IN, and P$4, PC15/OSC32_OUT) off the EXT header, rather than pins 21 and 22 (P$2, PC13/TAMPER-RTC and P$3, PC14/OSC32_IN). That is the way I have gone.

But, to me, getting back to 0.1" grid is more important. So I am happier with the changes than without.

Posted 5 years ago #
poslathian
LeafLabs

will link to the schematics once we push to git. I think theyre already in the svn (which is officially deprecated by the way). Sorry all, the BUT did not make it out to a header...we all agreed it was more important to have a GND pin on the header...as in, every header gets a ground.

I cant speak for the RTC stuff since I havnt looked in to it that much. For now I'll say....hmmmm...interesting.

Thats it for Rev5 though, there were a lot of subtle changes we wanted to make but didnt for timing reasons (there will be an inventory gap at this point. Maybe some distributors still have some stock...) Probably in mid october well be doing this all over again for Rev6!

BUT - the header location issue, as had been pointed out, has to be locked down so that people can build off of it with confidence. That is now the case. The 21/22 pins that were moved off the header are conveniently positioned on the 1/10" grid. Also a great many thoughtful silk changes were pushed.

The confusion about the pc9/d38 issue i think is a conventions problem. I kept saying "pin 38" but what i meant was d38. d38 is not a pin on Maple, it is a pin on the stm32, it is the reference number in the wirish library. So from now on, when referencing software-accessible pins we should say "d#" as in "d1,d2,d3" etc. And if you mean the physical pin, you mean pin 1, pin 2...etc. Incidentally, the only discrepancy between these two is d38. There is no pin 38.

Of course, libmaple is completely agnostic of this 1-38 numbering scheme, which is invented inside of wiring. The real pin numbers are the PXX (as in PC9, PB8, ...). This gets a little messy around the JTAG pins, which happen to be GPIO's also. And the numbers, internally, go up to 42 or something...but that port isnt really intended to be used for anything but jtag. And its intentionally not documented that those pins can be GPIO. For the record, the JTAG port since on the 1/20" grid...

Posted 5 years ago #
leaflabsandy
Member

Quote: "Additionally, the second VCC pin on the bottom left header has been replaced with VDDA, the analog voltage."

Reply: From the reset pin on the six pin header ... reset,Vcc/3.3,Vcc/3.3,GND,GND,Vin.
What position, on this header, did you place the VDDA from the reset?

Posted 5 years ago #
okie
Administrator

it goes:
reset,Vcc/3.3,Vdda/3.3,GND,GND,Vin

Posted 5 years ago #
leaflabsandy
Member

Quote: "Probably in mid october well be doing this all over again for Rev6!"

Reply: Put yourself into a hardware developer's shoes. It is extremely expensive
to design multiple shields for Maple rev3, Maple rev5 and maybe Maple rev6!

I sure hope, if a user buys a Maple rev3 and two years from now he needs the
"same" Maple rev3 instead of the latest and greatest updated, newer, version that
he is able to purchase the same one! Please don't say "we no longer make that version!"

In printed circuit board design attention to details is very important. Being on grid, stacking design, current limiting, component availability / second sourcing are just a few of the many items that a PCB designer needs to be aware of to create a stable design.

Posted 5 years ago #
gbulmer
Moderator

Sorry all, the BUT did not make it out to a header...we all agreed it was more important to have a GND pin on the header...as in, every header gets a ground.

I agree with that philosophy too. It would have been good to have the buttons on headers, but I've had a similar problem; too many useful signals, and not enough pins :-)

I cant speak for the RTC stuff since I havnt looked in to it that much. For now I'll say....hmmmm...interesting.

Yes, it would have been nice to have the RTC crystal oscillator pins tracked together to a common place, but I agree ...

... - the header location issue, as had been pointed out, has to be locked down so that people can build off of it with confidence. That is now the case.

It's done now - ship it.

The confusion about the pc9/d38 issue i think is a conventions problem. I kept saying "pin 38" but what i meant was d38. d38 is not a pin on Maple, it is a pin on the stm32, it is the reference number in the wirish library. So from now on, when referencing software-accessible pins we should say "d#" as in "d1,d2,d3" etc. And if you mean the physical pin, you mean pin 1, pin 2...etc.

I think there is still some ambiguity.
The d# is a high-level Maple library view of the STM32F, created in the Maple headers/library.
Using the d# for software accessible pins is simple and clear.

I was using "P$4" to mean the pin number on the STM32F103R 64-pin LQFP package, which corresponds with the Eagle CAD.
As an example d36 = P$38.
Then, if I've understood, d38 = P$40.

Physical pins (on headers) are unambiguous as they use the Maple library names, but just don't go as high, so ditching the 'd' is okay.

Posted 5 years ago #
poslathian
LeafLabs

to use llandy's forum conventions:

Quote: Put yourself into a hardware developer's shoes. It is extremely expensive
to design multiple shields for Maple rev3, Maple rev5 and maybe Maple rev6!

Reply: "- the header location issue, as had been pointed out, has to be locked down so that people can build off of it with confidence. That is now the case. " - However minor improvements like silk changes, adjustments to the power supply/selection/regulator circuit, non-functional component changes (cap values, rvalues etc), are all fair game in my opnion, and we will continue to improve these minor aspects to the best of our ability.

Posted 5 years ago #

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