Ii bus board, v2, with pullups

General
21

I would also be interested in the board and necessary parts if you are ordering

22

Great, thanks for the confirmation! On the picture above it does not look as if modifying the teletype would be more elaborate than building the bus board.
I will contemplate about it a bit since I already have the old bus board. On the other hand the board is cheap enough to enjoy the extra i2c connectorsā€¦

23

ok, iā€™ve had an even better idea for a potentially more elegant solution.

TT is (wonderfully) only one board. the i2c ā€œbus boardā€ could be a thin mezzanine, that connects to both the power jack (with a 5x2 female connector) and the i2c jack (with a 3x2 female connector).

there would then be a load of 3x2 male connectors on the back for i2c, and a male power connector (so there wonā€™t need to be redundant cabling.) the extra regulator and resistors can be hidden on the board. all in all it should be an elegant (and cheap) solution.

of course, iā€™ve already ordered some of yesterdayā€™s version and that will also be totally fine. so iā€™ll only make time to draw up this new version if there are other people interested.

12 Likes
24

Definitely interested. Hoping this ecosystem expands wonderfully and I want a to welcome all my potential new friends.

1 Like
25

Oh, I just ordered the original new bus board PCB - I did not really understand the idea of the new one, technically it does not make any difference, does it?

26

cough

:stuck_out_tongue:

3 Likes
27

Also interested in the mezzanine solution, as in addition to solving the ā€œpull-up situationā€ & providing more i2c connectors it also seems to be a more mechanically sturdy solution than the small bus board PCB.

28

I dont have any trilogy module so iā€™ll only have 1 txO connected to my TT. Will this still be a problem for me?

29

@sam haha, whoa that is embarrassing. i need to improve my reading comprehension skills.

@Leverkusen it will do the exact same thing. this is simply ergonomics.

1 Like
30

In terms of the ergonomics, I found trying to get 3 modules connected to TT and the previous I2C board tricky enough with my current set of I2C cables.Iā€™m wondering if the bus board would be better than a mezzanine solution? Of course, I could also just make myself some longer cables.

1 Like
31

I actually think the ideal is to have both designs available. The best very much depends on the design of the case.

Itā€™s also important to emphasise that whichever solution you choose, beware of short circuits.

1 Like
32

Yes, dummies on the not used males could be smart - would be a bummer when it falls off the tt in a portable case and then touches the power distributionā€¦:zap:

Thatā€™s the good thing about ribbon cables!

33

So, I ordered a v1 bus board just a bit ago. Sounds like the limit for that is 4 devices?

If I wanted to use 2 Ansibles (1 for grid, 1 for arc), a White Whale, a TXo and a TXi, do I need the v2 bus board? I suppose I might add Earthsea at some point as well, oh, and Just Friends, almost forgot about thatā€¦

Definitely interested in the v2 bus board!

34

Iā€™m wondering if you could connect the mk1 board to the mk2?

1 Like
35

ok-- i think this will be the ā€œfinalā€ teletype ii expander. connects directly to the back of the TT. 12 headers. power pass-through. i2c pullups set at 2.2k, bringing total i2c pullup resistance to 1.8k. notched for access to reset switch (if youā€™re programming the firmware and added the switch, that is)

the regulator and resistors are in the middle of the sandwich:

Order from OSH Park

$15 for 3. i just ordered a batch for testing.

here are the source files: tt-i2c-v3.zip (18.7 KB)

4 Likes
36

of course, now that iā€™ve ordered, it seems like this board should have the i2c connectors rotated to 90 degrees so cables escape vertically, not stacking up in layers horizontally. opinions?

37

Iā€™m having a hard time imagining the orientation of the board relative to the teletype because Iā€™m not looking at the back of my teletype right now. But it would be nice if the cables were oriented the same way on all devices, with the ground in a consistent position. (Though I believe Ansible is the odd one out on the position of ground if I remember correctly?)

38

thatā€™s a good point. perhaps each row could be a different direction. i find a single fold tends to make routing easierā€¦

39

@tehn - thanks for putting these together. Iā€™ve ordered a set of each from OshPark to test out. Both look great - Iā€™m excited to experiment with them. :slight_smile:

40

Just adding myself to the list of interested people. I donā€™t need this white yet, but once the txo/txi are ready Iā€™ll be up to 5 modules on my tt.

1 Like