[Featured][Dev] PindurTI (Best Thread 2005)

[Jim e]

Its not quite the same is it? I mean two ports in a dasiy chain usually means one port is in and one is out, in this case they would have to be defined in and out per calc. And then what happens if you need 3 calcs

Calc 1:
Link In
Usb Out
Calc 2:
Link Out
Usb In
Calc 3:
Link In
Usb Out

Doesn't TI have some kind of class room Hub?


Also whats new with pindur?

[threefingeredguy]

Short answer is not yet.


Long answer is usb8x doesn't have unit-to-unit yet.

Well, with TI-BASIC the Send( and Get( commands have an optional parameter of whether or not to use the linkport or the Mini-USB port. So in BASIC, one can do the daisy chain.

[Andy_J]

I thought those only worked with CBLs and the like?

[CoBB]

Also whats new with pindur?

The author has just come back from a three-day festival loaded with metal and rock music, sprinkled with a bit of blues and no computers within reach.

[Kalimero]

...loaded with metal and rock music, sprinkled with a bit of blues and no computers within reach. :P

Ugh, that must be what hell looks like :P

[CoBB]

Maybe, but then it's a quite nice hell.

[threefingeredguy]

I thought those only worked with CBLs and the like?

Ah, good point. I spose one could intercept the code with some kind of mem viewer and reverse engineer it, but that would be useless.

[Jim e]

Maybe, but then it's a quite nice hell.

OMG you poor bastard, all those trees and people and not a computer in sight. I sympathize with your plight, I hope others on the forum do as well.

[kv83]

He's crazy I tell you

[Timendus]

LOL (That is, if my throat would be any less sore...)

Anyway, you could do a daisy chain with just the link port, using one line for in and one line for out, as DigiTan suggested. But my way is much easier to wire and to code

[qarnos]

LOL (That is, if my throat would be any less sore...)

Anyway, you could do a daisy chain with just the link port, using one line for in and one line for out, as DigiTan suggested. But my way is much easier to wire and to code

I haven't been following this thread so I'm not sure what it is you are trying to do, but if you are talking about what I think you are, using one line for in and one for out wouldn't work. For instance, how would you differentiate between two consecutive 1's or 0's with only one line?

On a related note, I had an idea a few months ago to speed up link transfers. As has been noted, the are 4 possible states for the two lines. In order to send data you need to change states to signal a new bit, so that leave us with 3 states we could go to from any given state.

Therefore, if you could convert could data to base-3 before sending, you get an increase in efficiancy. Here is how you could do it:

If line 1 changes state (high to low or vice-versa) the "bit" is 0
If line 2 changes state, the bit is a 1
If both lines change state, the bit is 2

In theory, it would work, but the hard part would be the base-2 to base-3 conversion (and back again on the receiving end).

EDIT: How about using the "bit 2" state to alternate between send and receive states? Not sure if that would work, I haven't given it much thought.

[Timendus]

if you are talking about what I think you are, using one line for in and one for out wouldn't work. For instance, how would you differentiate between two consecutive 1's or 0's with only one line?

With timing. I used this principle with an IR port I once built with a friend:

- Short pulse is 0
- Long pulse is 1
- To send: Send average of long and short first, then 8 bits
- To receive: Clock first pulse, check for next 8 pulses if they take longer or shorter than the first

You could do the same with on line of the link port.

[qarnos]

if you are talking about what I think you are, using one line for in and one for out wouldn't work. For instance, how would you differentiate between two consecutive 1's or 0's with only one line?

With timing. I used this principle with an IR port I once built with a friend:

- Short pulse is 0
- Long pulse is 1
- To send: Send average of long and short first, then 8 bits
- To receive: Clock first pulse, check for next 8 pulses if they take longer or shorter than the first

You could do the same with on line of the link port.

Mmm... I don't like the idea of using timing on a calc. But if it works, it works!

[qarnos]

Mmm... I don't like the idea of using timing on a calc. But if it works, it works!

Just another thought... How about this. To send a bit, you alternate the status of one of the two lines. The receiving system acknowledge by either:

alternate both lines: plain ack.
alternate one line: ack plus send bit.

That way the receiver can acknowledge and send a bit at the same time. Then the original sender can ackowledge and send, so forth. If one calc has no data to send, it just responds with a plain ack.

Food for thought.

[Andy_J]

Then how do you send a bit to begin with?