PCF 8523 breakout board pins/ Hooking up to trinket

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payvement
 
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PCF 8523 breakout board pins/ Hooking up to trinket

Post by payvement »

Screen Shot 2017-08-29 at 10.40.59 PM.png
Screen Shot 2017-08-29 at 10.40.59 PM.png (547.93 KiB) Viewed 1799 times
I have a PCF 8523 and the pins aren't labeled-- there seem to be 6, 3 close to the edge of the board and 3 away from the board. any guidance on these pins would be helpful. Secondly, I wanted to hook it up to a adafruit trinket and I am a newbie so any additional advice would be helpful. (Note the picture below, it doesn't look like the normal one on the website)

Thank you!

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Franklin97355
 
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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by Franklin97355 »

That board was designed to connect to the Raspberry Pi but I find no information on which pins go where. I'll ask for you.

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by adafruit_support_carter »

That particular board was designed to fit on a Raspberry Pi GPIO header as shown on the product page:
https://www.adafruit.com/product/3386
If you mount it as shown, the pins will line up and you generally don't need to worry about them. It's similar to these other little boards meant to mount straight on the RPI header:
https://www.adafruit.com/product/3527
https://www.adafruit.com/product/3589

If you want to know the pins, you could look at a pinout digram for the Pi:
https://pinout.xyz
Note the picture below, it doesn't look like the normal one on the website
It looks correct to me. What do you see that's different? We have several RTC products. The same PCF8523 is available in a different breakout here:
https://www.adafruit.com/product/3295
Were you wanting that one?
I wanted to hook it up to a adafruit trinket and I am a newbie so any additional advice would be helpful
Do you have a 5V or 3V Trinket?

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by adafruit2 »

we connect to the 3V, gnd, and SDA, SCL pins for the Pi - so just back reference from those

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by payvement »

Thanks for the Replies,

I have a trinket with 5V logic-- so a 5V trinket.

Let's see if I got this straight-- I should look at the pinouts for the raspberry pi and figure out what the pins are from that. And then try to hook them up to the correct place in the Ada fruit trinket?

So if I'm looking at this correctly those six pins refer to 35-40 on that diagram
35 being BCM 19 Master in slave out (MISO)
36 being BCM 16
37 being BCM 26
38 being BCM 20 Master out slave in (MOSI)
39 being Ground
and 40 being BCM 21 Serial Clock (SCLK)
Using my picture above I can line up the circle on the pi with the circle on the 8523
So the top two holes on the picture I attached would be BCM 21 and Ground (in that orientation)
is that correct? If so, that makes sense.

Thanks again.

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by adafruit_support_carter »

I have a trinket with 5V logic-- so a 5V trinket.
Unfortunately you are going to have a difficult time connecting this to a 5V Trinket. This other version of the breakout is more suited for that application:
https://www.adafruit.com/product/3295

The one you have was designed specifically for the Raspberry Pi, and that was taken into account in its design. As a result, there is no voltage regulator to convert 5V to the 3V the PCF8523 wants. It just uses the available 3V power from the Pi GPIO. Not that it can't be done, but you are going to need to come up with a way to generate 3V power. You will also need to deal with the difference in logic levels for the I2C communication.

I also think you're looking at the wrong end of the GPIO pinout diagram. It goes in the "upper right" corner so that the board edge outline and thru hole match the Pi. I've labeled the pins in the photo below, but the 5V pins go nowhere, so you can't just apply 5V power an expect it to work. These pins are labeled NC (no connection) in the image below.
pins.jpg
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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by payvement »

Thanks for the reply. That's a bummer-- So you suggest I should get this package instead: https://www.adafruit.com/product/3295?

Before I get this-- Is there a better solution for keeping time on an ada fruit trinket in general or is this the best? Any advice would be helpful. I am trying to do something I think is simple-- during 2 hours on monday and wedensdays I want to have an LED blink. I was thinking the trinket with the battery pack (http://www.robotshop.com/en/adafruit-pr ... gIArfD_BwE)

and the clock with battery backup would allow the ada fruit to turn on and blink when the time was right. I think it makes conceptual sense. I have to use a trinket because it all has to fit in a tiny box.

Thank you for all your help!

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by adafruit_support_carter »

Yep. PID 3295 would work much better with a Trinket.

For your project though, it sounds like you are wanting to power it via battery? Would that be the only power source?

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by payvement »

Great I'll look up the PID 3295. Thank you!

Yep that's correct, I would want to power it with a battery so that it doesn't need to plugged into a wall. Would that battery pack work you think?

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by adafruit_support_carter »

The battery pack will work, but I'm concerned about how long it will run. It sounds like you are working with week-ish long time frames. I don't think the battery will power everything for that long without doing some more advanced tricks like going to sleep. Of course, a bigger capacity battery will power it longer, but even then might get you up to one week total at most. (very ROM guessing)

You're starting to get in the realm of lower power stuff, which can get tricky. If you just want to get these parts and put them together for the fun and learning, go for it. Just trying to set expectations for how long you can power by just hooking up a battery.

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by payvement »

Right I was seeing some information on that online-- using the clock to wake up the Arduino. You're right, that seems like the correct solution. Is that doable with the arduino Trinket and the PID 3295?
It looks like this person did it with the trinket (that project seems a lot more complicated but correct proof of concept): http://rwsarduino.blogspot.com/2014/02/ ... ender.html

Is that on the right track?

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Re: PCF 8523 breakout board pins/ Hooking up to trinket

Post by adafruit_support_carter »

It's on one of the right tracks. Seems like it could at least provide a good starting point for you to use as reference and couple that with researching what the code is doing.

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