User avatar
FLYFISH TECHNOLOGIES
Posts: 1750
Joined: Thu Oct 03, 2013 7:48 am
Location: Ljubljana, Slovenia
Contact: Website

Re: MCP23017 Pins @ boot (Initial State)

Sat Dec 28, 2013 6:33 pm

Hi,
nixem wrote:But if I understand correctly I will be able to choose the initial state with the proper configuration of resistors.
Correct.


Best wishes, Ivan Zilic.
Running out of GPIO pins and/or need to read analog values?
Solution: http://www.flyfish-tech.com/FF32

nixem
Posts: 16
Joined: Mon Sep 16, 2013 5:10 am

Re: MCP23017 Pins @ boot (Initial State)

Sat Dec 28, 2013 6:36 pm

FLYFISH TECHNOLOGIES wrote:Hi,
nixem wrote:But if I understand correctly I will be able to choose the initial state with the proper configuration of resistors.
Correct.


Best wishes, Ivan Zilic.
How is that? Did you see the diagrams I linked you to? You said you might be able to help me understand where/what resistor

User avatar
FLYFISH TECHNOLOGIES
Posts: 1750
Joined: Thu Oct 03, 2013 7:48 am
Location: Ljubljana, Slovenia
Contact: Website

Re: MCP23017 Pins @ boot (Initial State)

Sat Dec 28, 2013 6:43 pm

Hi,
nixem wrote:Did you see the diagrams I linked you to?
No. Where did you link it ?
nixem wrote:You said you might be able to help me understand where/what resistor
Yes, not a problem... let's find out first where is the diagram...


Best wishes, Ivan Zilic.
Running out of GPIO pins and/or need to read analog values?
Solution: http://www.flyfish-tech.com/FF32

nixem
Posts: 16
Joined: Mon Sep 16, 2013 5:10 am

Re: MCP23017 Pins @ boot (Initial State)

Sat Dec 28, 2013 9:40 pm

FLYFISH TECHNOLOGIES wrote:Hi,
nixem wrote:Did you see the diagrams I linked you to?
No. Where did you link it ?
nixem wrote:You said you might be able to help me understand where/what resistor
Yes, not a problem... let's find out first where is the diagram...


Best wishes, Ivan Zilic.
These are the relays im using... http://www.sainsmart.com/8-channel-dc-5 ... logic.html Although when I download the Rar file at the bottom of the product description (right below the videos) It shows a different relay in the eagle files... weird... skinny relay

User avatar
FLYFISH TECHNOLOGIES
Posts: 1750
Joined: Thu Oct 03, 2013 7:48 am
Location: Ljubljana, Slovenia
Contact: Website

Re: MCP23017 Pins @ boot (Initial State)

Sat Dec 28, 2013 11:18 pm

Hi,

Ok, I suppose that you have a "middleware" circuit with two resistors and a transistor proposed on the right side here:
https://docs.google.com/file/d/0B5-HND9 ... sp=sharing
(By the way, most likely, this diagram includes a transistor label typo - missing one "2" in its name - should be 2N2222.)

So, what you need to do with this "middleware" is to remove 10k pull-down resistor and add pull-up resistor towards 3.3V. I'd take lower value of this new resistor, something around 3k3 - 4k7.


Best wishes, Ivan Zilic.
Running out of GPIO pins and/or need to read analog values?
Solution: http://www.flyfish-tech.com/FF32

User avatar
Richard-TX
Posts: 1549
Joined: Tue May 28, 2013 3:24 pm
Location: North Texas

Re: MCP23017 Pins @ boot (Initial State)

Sun Dec 29, 2013 9:42 am

All the really needs to happen is to jumper out the leds. Then the circuit will work.
Richard
Doing Unix since 1985.
The 9-25-2013 image of Wheezy can be found at:
http://downloads.raspberrypi.org/raspbian/images/raspbian-2013-09-27/2013-09-25-wheezy-raspbian.zip

Return to “Interfacing (DSI, CSI, I2C, etc.)”