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Posted by kohlschuetter 4 days ago

The Serial TTL connector we deserve(kohlschuetter.github.io)
102 points | 76 commentspage 2
wildzzz 1 day ago|
Ideally you wouldn't need to expose a TTL serial debug port to begin with. Maybe on a prototype you would want this but I'd rather just have a single connector that can expose everything (jtag or swd). Bonus points if the interface chip is on the board so it's just a USB port
eqvinox 1 day ago||
FUSB307B is amazing for this, it has a hardware DBG output pin indicating that a USB-C debug accessory mode connection has been made. Perfect for connecting a mux and putting SWD & serial on some USB-C pins.

Too bad there's no standard for debug accessory connections. Also, at that point (putting a USB-C TCPC on your board) you might as well do full usbserial…

NB: there's no orientation detection in debug accessory mode.

Geof25 1 day ago||
Well the first problem you will hit I'd that very likely you will need to protect or isolate those lines from ESD. This will raise price of device and it will get denied just in these grounds.
exmadscientist 1 day ago||
ESD diode costs are nothing compared to the connector headers or even dealing with the mechanical complications of exposing Just One More Thing. Seriously, they're cheap.
amelius 1 day ago||
I always wonder why Molex makes only black and white connectors. This makes it needlessly difficult to use different connectors for different purposes. Same with phoenix contact but there it's mostly green terminal blocks. Is it so difficult to just offer some more colors?
ted_dunning 2 hours ago||
You can solve that problem with a bit of heat shrink if you really want to.
Aurornis 1 day ago||
They’ll make them in any color you want if you order enough.

Adding more colors would multiply their logistic and inventory requirements, which are already hard with so many different connectors multiplied by number of pin options. Multiplying that even further by number of colors that most people would never buy isn’t a win.

amelius 1 day ago||
I mean, LEGO can make the same brick in many different colors. With much lower tolerances.
Aurornis 1 day ago|||
Making them in different colors is the easy part. Inventorying and selling them is the hard part.

LEGO knows exactly the demand for every color of every piece because they make the sets.

If they made 10 different colors of the connector, they’d still sell mostly white and black. Then the rest would sit on shelves and take up manufacturing line time and shelf space. Then they’d have to reprice them to sell off the colors that weren’t moving.

LEGO has none of these problems. Everything goes into a set or retail package they make. The individual loose bricks go into a limited number of options at a few retail stores.

kalleboo 1 day ago|||
Have you seen what LEGO costs though?
mmoskal 1 day ago||
If you want something with very small pcb footprint and DIY cheap cable try Hack connect https://arcade.makecode.com/hardware/dbg
theamk 1 day ago||
on Aliexpress, Julet M6 pigtail pair is $2.99, while USB-TTL breakout (with female USB-C connector) is $1.40 - even for nice CP2102 with unique serial number.

If you have a portable device which needs serial connector, don't bother with weird connector and bespoke adapters which will get lost. Go for USB-C directly. As an extra bonus, USB-C is significantly more electrically rugged than raw UART input.

(this does not apply if you have some sort of multi-port serial port server, but those are pretty rare, and most likely use real RS232 voltages anyway)

aardvarkdriver 1 day ago||
FWIW, my initial thought here was not transistor-transistor logic but through-the-lens (re: camera light metering). I was excited to learn that maybe someone had waded through the stovepiped mess of TTL metering across camera manufacturers and developed an open-source solution.
skybrian 1 day ago||
Ideally I'd like to standardize on something that disconnects easily rather than breaking a different part.
andrewshadura 1 day ago|
I found Julet connectors incredibly hard to disconnect once plugged in. I can’t get a good grip on anything.
MrBuddyCasino 1 day ago|
They’re good for eBikes because they’re sturdy and don’t disconnect easily, but I dread un-/plugging them.