74HC595 and 74HC597 questions
Archiver
Posts: 46,084
I'm thinking about using 74HC595's and 597's to expand the number of
input pins on my Stamp, and provide some protection from damaging its
pins: The chips are 50 cents to replace, the stamp isn't.
I also want to use a pair of them to make a simple two digit LED
display for diagnostics, and I'm told that I'll need one for each
digit, which makes sense, but I'm also told that no matter how many i
have used, i'll only need 3 IO pins from the Stamp, and i cant figure
out how.
electronguy wrote:
>I am putting together a 3 LED display right now and am using 74hc595
>shift registers. You use one chip per LED but only 3 BS2 lines even
>if you add 20 digits! I like all the flexibility these give you.
>One thing that I did was to program it so that all the segments were
>on the one side and DP on the other. You will understand once you
>look at the documentation.
>www.phanderson.com has all the info in there stamp section on doing
>this.
I can't find anything at phanderson on this topic, so does anyone
know what i'm missing?
-Chris
input pins on my Stamp, and provide some protection from damaging its
pins: The chips are 50 cents to replace, the stamp isn't.
I also want to use a pair of them to make a simple two digit LED
display for diagnostics, and I'm told that I'll need one for each
digit, which makes sense, but I'm also told that no matter how many i
have used, i'll only need 3 IO pins from the Stamp, and i cant figure
out how.
electronguy wrote:
>I am putting together a 3 LED display right now and am using 74hc595
>shift registers. You use one chip per LED but only 3 BS2 lines even
>if you add 20 digits! I like all the flexibility these give you.
>One thing that I did was to program it so that all the segments were
>on the one side and DP on the other. You will understand once you
>look at the documentation.
>www.phanderson.com has all the info in there stamp section on doing
>this.
I can't find anything at phanderson on this topic, so does anyone
know what i'm missing?
-Chris
Comments
>I'm thinking about using 74HC595's and 597's to expand the number of
>input pins on my Stamp, and provide some protection from damaging its
>pins: The chips are 50 cents to replace, the stamp isn't.
>
>I also want to use a pair of them to make a simple two digit LED
>display for diagnostics, and I'm told that I'll need one for each
>digit, which makes sense, but I'm also told that no matter how many i
>have used, i'll only need 3 IO pins from the Stamp, and i cant figure
>out how.
Its really easy! Each chip has a pin used to cascade to the next. Lets
talk about hc595 for now. Connect all the Clock pins together and to the
stamp. Connect all the latch strobe pins together and to the
stamp. Connect the data IN of the 1st 'hc595 to the stamp. Connect the
data OUT of the 1st hc595 to the data IN of the next hc595. Keep adding
more hc595s to the end as you need them.
It gets a tiny bit more complicated if you want both inputs and outputs on
the same 3 pins - but not by much. You will need a small resistor - 2k2 or
so is fine. Connect the clock and latch pins you already have to the Clock
and Parallel Enable (P/S) on the hc597s. Connect the data IN of the 1st
hc597 to GND, connect its data OUT to the data IN of the next, etc. When
you get to the last hc597, connect its data OUT to the data line going to
the stamp THRU the 2k2 resistor. In other words, there is a 2k2 resistor
between the data out of the last hc597 and the stamp.
The sequence is: turn the stamp data pin to input, send out as many clock
pulses as you have input bits and read the data from the data pin. When
you have gotten all the input data bits, turn the stamp data pin to an
output and send as many clock and data bita as you have outputs. Then
pulse the latch strobe pin - this updates both the input and output
shift registers at the same time.
dwayne
Dwayne Reid <dwayner@p...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax
Celebrating 16 years of Engineering Innovation (1984 - 2000)
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.
Ok, thanks a lot, i get it now. That is simple.
-Chris
--- In basicstamps@egroups.com, Dwayne Reid <dwayner@p...> wrote:
> Its really easy! Each chip has a pin used to cascade to the next.
>Lets talk about hc595 for now. Connect all the Clock pins together
>and to the stamp. Connect all the latch strobe pins together and to
>the stamp. Connect the data IN of the 1st 'hc595 to the stamp.
>Connect the data OUT of the 1st hc595 to the data IN of the next
>hc595. Keep adding more hc595s to the end as you need them.
>It gets a tiny bit more complicated if you want both inputs and
>outputs on the same 3 pins - but not by much. You will need a small
>resistor - 2k2 or so is fine. Connect the clock and latch pins you
>already have to the Clock and Parallel Enable (P/S) on the hc597s.
>Connect the data IN of the 1st hc597 to GND, connect its data OUT to
>the data IN of the next, etc. When you get to the last hc597,
>connect its data OUT to the data line going to the stamp THRU the2k2
>resistor. In other words, there is a 2k2 resistor between the data
>out of the last hc597 and the stamp.
>
>The sequence is: turn the stamp data pin to input, send out as many
>clock pulses as you have input bits and read the data from the data
>pin. When you have gotten all the input data bits, turn the stamp
>data pin to an output and send as many clock and data bita as you
>have outputs. Then pulse the latch strobe pin - this updates both
>the input and output shift registers at the same time.
>
> dwayne
>
>
>
> Dwayne Reid <dwayner@p...>
> Trinity Electronics Systems Ltd Edmonton, AB, CANADA
> (780) 489-3199 voice (780) 487-6397 fax
>
> Celebrating 16 years of Engineering Innovation (1984 - 2000)
>
> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> Do NOT send unsolicited commercial email to this email address.
> This message neither grants consent to receive unsolicited
> commercial email nor is intended to solicit commercial email.
for using the hc595 with the BS2. He does have info on using it with the
BasicX. I guess I'm getting senile [noparse]:)[/noparse] I could have sworn he had some info on
that, but after looking around a bit I found the code and info for the BS2
right in the BS2 Manual. It is the application notes dealing with serin and
serout. Page 353 version 1.9.
Sorry to misdirect you.