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sumdawgy
03-04-2010, 02:14 AM
Need help with 8-bit serial-in/serial or parallel-out chip.

·74HC/HCT595 made by Phillips

I'm using it with a Bs1-Ic to control some LEDs and Relays.

I can't get the unit to provide me the outputs to drive it's darlington associate.

Has anyone had experience with this?




Post Edited By Moderator (Joshua Donelson (Parallax)) : 3/9/2010 1:50:14 AM GMT

hover1
03-04-2010, 02:39 AM
Post the same question in a new thread is not going to get you a faster response, and double posts are not allowed.

You should take Mike's suggestion on reading the StampWorks chapter he cited.

·http://www.parallax.com/Portals/0/Downloads/docs/books/sw/Web-SW-v2.1.pdf

It explains how to communicate with the chip.

And like Mike suggests, the project really needs a BS2 chip.

Jim

sumdawgy
03-04-2010, 08:37 AM
While the topic is the similar. I don't believe I've double posted.

(I'm taking some more of Mike's advice in that I shortened & focused my question.)

In this case:

I'm asking if anyone has had experience in using this chip in this situation.
As opposed to advising me in my project.

I'm gratefull that my problem is being considered. Although I'm saddened that it has primarilly drawn me reprimands.

But thank you for the link, I will study that pdf tonite and see if it adresses my situation.

sumdawgy
03-04-2010, 08:39 AM
hover1 said...

And like Mike suggests, the project really needs a BS2 chip.


I addressed the selection of the Bs1 over the Bs2.·· in my origional "wordy" post.

And again in a later followup post.

I wish I could.· None of this would apply.

Franklin
03-04-2010, 08:58 AM
A subject on your post would be a nice start.

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- Stephen

BoeBot
03-04-2010, 09:04 AM
Hopefully you might find something helpful in here: http://tisu.it.jyu.fi/embedded/TIE348/Exercises/ex7/74hc595.pdf

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Change is inevitable - except from a vending machine.

Robert C. Gallagher

sumdawgy
03-04-2010, 09:15 PM
Franklin said...
A subject on your post would be a nice start.


True...it seems to be an "aborted" removal/rename?

sumdawgy
03-04-2010, 09:29 PM
hover1 said...

http://www.parallax.com/Portals/0/Downloads/docs/books/sw/Web-SW-v2.1.pdf



exercise 23 specifically deals with my application, and it DOES seem to indicate that the storage registers are persistent (unlike Dram).

I don't (yet) have their 10K resistor pulling the storage clock pin down. But it doesn't seem to keep the shift from operating?

Another thing I'm going to try...I have another chip to substitute for the current one ...

Thank you again for the link.

sumdawgy
03-04-2010, 09:34 PM
BoeBot said...
Hopefully you might find something helpful in here: http://tisu.it.jyu.fi/embedded/TIE348/Exercises/ex7/74hc595.pdf


thanks...
Studied it for almost a month now....I've practically memorized that manual.

PJ Allen
03-05-2010, 02:28 AM
You could use a '595 with a BS1, that's not dreaming the imposssible dream, but it's going to cost you 5 I/O pins; if you don't want "full functionality" then you could use fewer.

sumdawgy
03-07-2010, 08:21 AM
PJ Allen said...
You could use a '595 with a BS1, that's not dreaming the imposssible dream, but it's going to cost you 5 I/O pins; if you don't want "full functionality" then you could use fewer.


Well project 23 from the last pdf & 2 others specifically dealt with the '595
But that project like my own only cost me 3 pins DATA/SHIFT/Storage (Latch)

http://forums.parallax.com/images/smilies/hop.gifBut I have some minor sucess...
I played with the code a bit......and got it to respond.·
At minimum, a "pause 20" following the HIGH/LOW (x) commands to the Data pin.
I suppose the pin was still changing to the desired level during shift.
Since I was driving low by default·then applying if-then· to decide to raise.
The data pin was still LOW even if changing b4 the shift.

I was also mistaken regarding the inability to·use pulsout·with the Bs1.
currently I'm using a 80,000 pulse length.
Bonus:·I have· been able to recoup some program space.

sumdawgy
03-07-2010, 09:14 AM
PJ Allen said...
·but it's going to cost you 5 I/O pins; if you don't want "full functionality" then you could use fewer.


Ahhh...· the MR(not)· and OE(not).· I understand.
Truth be told, MR would most definitly be a program space saver (during inititialization) if I were using more than one 595.

PJ Allen
03-07-2010, 09:52 PM
..

The Clear and Output Enable are kind of optional, whether to have access to them·under S/W, but you have to take care of them just the same by tying them HI/LO as appropriate.

[I think that's what we're talking about here.]

sumdawgy
03-08-2010, 05:17 AM
PJ Allen said...

..

The Clear and Output Enable are kind of optional,.....

[I think that's what we're talking about here.]


Yep....that was it.· And yeah one high one low as appropriate..· :)

sumdawgy
06-08-2010, 04:38 AM
In the end, I dissasembled practically my entire Shift board before I discovered that I'd NOT connected my darlington's "COM" pin to +!2v. It hung free, lost in the harneses.

Score yet another one for overconfidence. Although from that humbling expeience, I ended up with a seperate relay board on the wiring harness. And (in my estimation) a far more reliable/safer application.

Thanks to life's myriad distractions, I only just now poasted the completed project details. (Although there are a few minor details to be dealt with.)

I DO thank everyone for thier help.

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Before you criticize someone, walk a mile in his shoes. That way if he gets angry, he'll be a mile away and barefoot. - unknown