Teensy 4.0 Breakout Kit

[DaQue]

Does it work with older audio boards?

[PaulStoffregen]

Yes, the breakout board works with the older shields. Every beta tester got the Rev B audio shield. Works great.

It probably will also work with the ancient Rev A audio shields, but that was never tested.

[KurtE]

Does it work with older audio boards?

If you mean Paul's breakout board, I am pretty sure we were all using the older (Rev B) Audio boards with the beta

[DaQue]

Thanks. After Tensyduino is out of beta ill start playing around with stump and may be a pcb.

[Joena]

Yes its actually easier than you think. I came across a HDMI shield that can be used with a T3.6 and I adapted it so you can use it with the T4. This is the shield post: https://forum.pjrc.com/threads/54711...l=1#post207850

And this is some results: https://forum.pjrc.com/threads/54711...l=1#post208337 The testing was done with 10" GoChic display.

Kind of put any further mods on hold because of higher priority testing.

Thx for your reply mjs513

[loglow]

Some updates:

• Added SD card bypass cap pads, moved SD socket a little.
• Removed redundant 3V3 and GND pads from Teensy footprint.
• Added ON button pads, moved VUSB-VIN switch a little.
• Added pads for TPD3S014 and two caps on bottom side, near USB host port.
• Added pads for nine various pullup resistors on bottom side.
• Updated and cleaned up some silkscreen markings.

Please keep any feedback coming!

Is that 1.5" x 2.6" overall?

2.6" x 1.4" with the rails, 2.6" x 1.0" without the rails.

Would it make sense to add a GND pad spaced with the 'ON' Pin pad to place a button there?

I think this is a good idea, I've added pads to accommodate a standard 4 x 3 mm tactile switch.

I'd recommend placing the USB host connector closer. The SD signals run at 50 MHz, which is pretty fast and definitely wants GND routed as close together with with CLK as possible. But USB host runs at 480 Mbit/sec, and there's already almost 2 inches of not well impedance controlled routing from the BGA to the end of that flex cable.

I'm not sure I can move it any closer with this board layout, so I hope it can be workable as-is. Any thoughts or suggestions?

Remember to use 2 capacitors for whatever USB current limit chip you choose. Try to resist the typical thinking that bigger must be better. I'd recommend 100 to 150 uF for the output cap, and 2.2 to 4.7 uF for the input cap. If space is an issue, that smaller cap wants to be as close as possible to the current limit chip, and the big output cap wants to be close to the USB connector.

Thanks. I'm planning on 2.2uF on the input and 100uF on the output. I was planning to go with the TPD3S014 for the time being. Why did you switch to the TPS2055A for your breakout? I noticed that the TPS2055A doesn't provide any ESD protection for the D+ and D- signals.

Also a good idea to place a decoupling capacitor close to the SD socket. Those tiny micro SD cards don't have space for much on-board capacitance. Especially if you run the power and ground wires across the board to reach the socket, you really want come capacitance close to the socket.

Do you think 100µF would be a reasonable value for this cap? I read something somewhere that suggested a value > the total capacitance of the card.

[madgrizzle]

Sorry for asking a seemingly stupid question, but what's the purpose of the carrier rails?

[MichaelMeissner]

Sorry for asking a seemingly stupid question, but what's the purpose of the carrier rails?

These are power rails, similar to the power rails on a traditional breadboard. Typically one rail would be ground and one rail would be 3.3v. Typically you would solder either a row of female/male headers on the data and 2 power rails.

For example, if you had an analog sensor (like a trimpot), you have the pins from the carrier rails adjacent to the data, so that you could use a cable with 3 wires to get all 3 values (data, ground, power). And it makes it fairly easy to move connections while you are debugging things if you use male or female headers.

In other boards by loglow (Talldog on Tindie) that have these carrier rails, you can remove them if you don't need them to save space (it is perforated to make it easier to snap off). For example, here is his/her revision D break out board for the Teensy 3.2:

• https://www.tindie.com/products/logl...ut-revision-d/

[madgrizzle]

Thanks.. I thought that might be the case but wasn't sure.. You'll have to jumper to it however you want it set up, I assume, since they don't seem to be connected to anything.

One thing I'm interested in is adding a wifi module to the T4 and it looks like using this breakout board, I could build a shield that accepts a esp32 devkit board without having to deal with surface mount components. I can hand build some simple through-hole PCBs, but I gave up on SMD work.

[defragster]

Something like this would be a major rewrite … but have both USB cables point to the same end - Teensy 4 on 'top' and the USB Host moved from far end to the underside. That underside placement shown here in RED BOX on top layer. The USB Host pins are already right there. The SD Socket would be unchanged on top. But the T_4 and pins would shift right to allow USB Host through hole pin clearance. This would require a shift of the bottom layer - and the T_4 pins sliding would shift the nice layout of the bottom pins on the edges as well. Would add height of the USB Host connector to the design when used. Would be less if a Female USB like PJRC breakout was used instead of the standard tall host plug.

Drastic change - but would ideally make sure the USB Host wasn't compromised - or those signals didn't compromise anything else in transit across the PCB - as long as the SD and USB host don't bother each other.



Oh - and cool the POWER button fit in - the i2c pullups look like a good add too.

[DaQue]

What do you think of the SD card connector on a separate tiny pcb? The flex pcb could already be soldered to it

[defragster]

What do you think of the SD card connector on a separate tiny pcb? The flex pcb could already be soldered to it

That might be ideal - and sold stand alone - of course that means a way to just get the USB Host pins to the PCB without it is needed too. Of course than looks like crossing cables with USBHost to PCB and SD cabled out through it??

During the Beta the USB Host developments show it to very generally useful for transferring bulk data - including SD cards in USB dongles - and the opportunity of connecting various/multiple devices.

In many cases just getting USB Host adapted to a T4 might be important for some - given so many variations of 'perfect'

[loglow]

If I were to make a few pre-release breakout boards, are there some folks who'd be interested in putting the USB host port through some rigorous testing? Shipped out free, of course. Let me know and we can work out the details from there.

Drastic change - but would ideally make sure the USB Host wasn't compromised - or those signals didn't compromise anything else in transit across the PCB - as long as the SD and USB host don't bother each other.

There's one big issue with this proposed layout, and it's the same problem that already exists with the 3.5/3.6 Standard breakout: the Teensy doesn't sit high enough above the breakout PCB for its onboard Micro USB port to be accessible when a full-size USB port is in that spot. If (and only if) the Teensy is socketed with low-profile headers, then there's enough clearance. I want to avoid that situation for this board because, like you said below, the USB host port is a very useful addition.

...here is his/her revision D break out board...

I use he/him pronouns and my real name is Dan, but I don't care if people call me Tall Dog (business name) or loglow (username). Thanks for explaining purpose of the carrier rails! They're a very cheap addition that's very useful to some, and they're easy to remove if not needed.

What do you think of the SD card connector on a separate tiny pcb? The flex pcb could already be soldered to it

I'm hesitant to do this. Mostly because I still want to break out those 6 GPIO pins for general purpose use, so at that point why not just have pads for the Micro SD as well? At some point I might resurrect my Micro SD extension board/cable with an added panel-mount option though.

[defragster]

If I were to make a few pre-release breakout boards, are there some folks who'd be interested in putting the USB host port through some rigorous testing? Shipped out free, of course. Let me know and we can work out the details from there.

I'd connect for testing.

There's one big issue with this proposed layout, and it's the same problem that already exists with the 3.5/3.6 Standard breakout: the Teensy doesn't sit high enough above the breakout PCB for its onboard Micro USB port to be accessible when a full-size USB port is in that spot. If (and only if) the Teensy is socketed with low-profile headers, then there's enough clearance. I want to avoid that situation for this board because, like you said below, the USB host port is a very useful addition.

@loglow - check RED box around USB Host connect on post #35 - "That underside placement shown here in RED BOX on top layer." - just copied on top to show spacing and ease of hacking in MSPaint. That doesn't make it a workable solution - but the cable passage was noted.

I use he/him pronouns and my real name is Dan, but I don't care if people call me Tall Dog (business name) or loglow (username). Thanks for explaining purpose of the carrier rails! They're a very cheap addition that's very useful to some, and they're easy to remove if not needed.
I'm hesitant to do this. Mostly because I still want to break out those 6 GPIO pins for general purpose use, so at that point why not just have pads for the Micro SD as well? At some point I might resurrect my Micro SD extension board/cable with an added panel-mount option though.

Opps - I answered @DaQue - thinking it was @loglow … re separate SD cable -

[DerekR]

Hi Dan - I presume by "rigorous testing" you mean a mechanical/assembly workout?? Count me in for any alpha/beta testing!

FWIW - I would certainly vote for retaining access to the GPIO pins.

Derek

[loglow]

I'd connect for testing.

Count me in for any alpha/beta testing!

Just sent you guys private messages to follow up about this.

[DerekR]

Thanks, however there is nothing in my PM inbox yet (5:15pm) - don't know how long it usually takes...

[KurtE]

If I were to make a few pre-release breakout boards, are there some folks who'd be interested in putting the USB host port through some rigorous testing? Shipped out free, of course. Let me know and we can work out the details from there.



There's one big issue with this proposed layout, and it's the same problem that already exists with the 3.5/3.6 Standard breakout: the Teensy doesn't sit high enough above the breakout PCB for its onboard Micro USB port to be accessible when a full-size USB port is in that spot. If (and only if) the Teensy is socketed with low-profile headers, then there's enough clearance. I want to avoid that situation for this board because, like you said below, the USB host port is a very useful addition.



I use he/him pronouns and my real name is Dan, but I don't care if people call me Tall Dog (business name) or loglow (username). Thanks for explaining purpose of the carrier rails! They're a very cheap addition that's very useful to some, and they're easy to remove if not needed.



I'm hesitant to do this. Mostly because I still want to break out those 6 GPIO pins for general purpose use, so at that point why not just have pads for the Micro SD as well? At some point I might resurrect my Micro SD extension board/cable with an added panel-mount option though.

It would be interesting to try your method out... I am building some of my own boards, which are a pain with those ribbon cables...

As for putting it through it's paces, I do still have lots of USB work left to try out. Things like getting my branch to support multiple BT devices to be in good enough shape to get pulled in...

[firehopper]

Just sent you guys private messages to follow up about this.

I have a t4 and would love to try an help too. I have a bunch of different usb devices I could try, including a usb sound card, a usb bluetooth thingy, 2 wireless mice, and a couple thumb drives and a HD to usb adaptor and a m2 to usb adaptor

[loglow]

Thanks, however there is nothing in my PM inbox yet (5:15pm) - don't know how long it usually takes...

Don't know what happened there, but I resent it.

I have a t4 and would love to try an help too. I have a bunch of different usb devices I could try, including a usb sound card, a usb bluetooth thingy, 2 wireless mice, and a couple thumb drives and a HD to usb adaptor and a m2 to usb adaptor

PM sent.

As for putting it through it's paces, I do still have lots of USB work left to try out. Things like getting my branch to support multiple BT devices to be in good enough shape to get pulled in...

No prob. Let me know if things settle down and you'd like to hop in!

[mjs513]

Don't know what happened there, but I resent it.



PM sent.



No prob. Let me know if things settle down and you'd like to hop in!

Well, if you want another guinea pig to test your board let me know. I pretty much attached everything under sun to the T4 so far.

[defragster]

I got the PM and replied … @loglow - KurtE as well was suggesting his USB Host work would be well suited to inclusion.

[loglow]

Well, if you want another guinea pig to test your board let me know. I pretty much attached everything under sun to the T4 so far.

Thanks! PM sent.

I got the PM and replied … @loglow - KurtE as well was suggesting his USB Host work would be well suited to inclusion.

Thanks! I just sent KurtE a PM too.

[loglow]

Latest revision. This is likely to be the first limited pre-production run of boards and cables:

• Modified flex cable shape for better clearance around the VUSB pin header.
• Routed all traces and corrected some silkscreen markings.
• Reversed order of breakout pins 34-39 for easier routing.
• Initial component selection (see below).

Flex cable is symmetrical and can be used with either side facing up:



Breakout board top:



Breakout board bottom:



Components*:

• C1, C3: Samsung CL31A107MQHNNNE
• C2: Samsung CL21B225KPFNNNE
• U1: Texas Instruments TPD3S014DBVR
• Pullup resistors: Panasonic ERJ-6GEYJ472V
• SD socket: Amphenol 10067099-200LF
• Flex connector: Wurth 686110148922
• Tactile button: C&K PTS820 J20M SMTR LFS
• Slide switch: Generic SS12D00G3 (or 3-pin male header w/ jumper)
• USB jack: Amphenol UE27AC54100
• Battery holder: MPD BK-885
• Battery: Panasonic CR1220

*Most components will be replaced with generic equivalents over time as functional testing permits.

Thanks to all the volunteer beta testers! I'm very interested to see how smoothly assembly goes, and how well the USB host port functions in this arrangement.

[defragster]

Latest revision. This is likely to be the first limited pre-production run of boards and cables:
...
Thanks to all the volunteer beta testers! I'm very interested to see how smoothly assembly goes, and how well the USB host port functions in this arrangement.

That looks very good @loglow. Excited to assemble and see it work! The Teensy 4 is awesome - breaking all out like this give full utility.

Nice the Flex Cable is symmetric, also that it terminates in the connector and not soldered on both ends.

CR1220's are nicely smaller, assuming those won't ship ( I have a pack ) - any other parts that won't be included?

No gratuitous LED for Power - which actually was telling with what resulted in the 'white wire' edit during Beta. But no open space near 3V3 - or to drop pin or extra parts on a very full PCB.