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by westwol
Wed Mar 27, 2019 3:43 pm
Forum: Troubleshooting
Topic: MCP23s17 issues!
Replies: 3
Views: 135

Re: MCP23s17 issues!

The behavior you are experiencing is true because of the way you have wired the control signals to both chips maybe this will clear things outspi_cascade.png I tried the set up above, and now the second chip is not being triggered at all even when trying. Also tested this commands with the same con...
by westwol
Wed Mar 27, 2019 5:33 am
Forum: Troubleshooting
Topic: MCP23s17 issues!
Replies: 3
Views: 135

MCP23s17 issues!

Hi there! I was trying to get 2x MCP23s17 set up in cascade this way: https://i.imgur.com/PRnQFRB.png The issue is that I'm unable to access to each chip individually. For example, when I run this code: import spidev import RPi.GPIO as GPIO class MCP23S17(object): """This class provides an abstracti...
by westwol
Tue Mar 05, 2019 5:34 pm
Forum: HATs and other add-ons
Topic: I2C I/O PORT EXPANDER QUESTION
Replies: 37
Views: 1688

Re: I2C I/O PORT EXPANDER QUESTION

Do you know many PCA9685 does raespberry support? The looks easier with this chip because of its libraries.
by westwol
Tue Mar 05, 2019 5:11 am
Forum: HATs and other add-ons
Topic: I2C I/O PORT EXPANDER QUESTION
Replies: 37
Views: 1688

Re: I2C I/O PORT EXPANDER QUESTION

Thanks both of you for your answerings. Sorry, I couldn't explain myself well. Let's try again. I should able to control 260 ports that must output 5V (HIGH) when active not necessarily a LED, it could be a wire to a relay that activates something. (Just one output will be enabled at a time, so I do...
by westwol
Mon Mar 04, 2019 11:59 pm
Forum: HATs and other add-ons
Topic: I2C I/O PORT EXPANDER QUESTION
Replies: 37
Views: 1688

Re: I2C I/O PORT EXPANDER QUESTION

First of all, I appreciate the time you take to help me. 1. What I am trying to control: I want to control a LED state (HIGH/LOW), but I should be able to change the state between 260 GPIO's where the leds will be plugged. (Only one output (led) will be enabled at a time). Output must be: 5 V. The p...
by westwol
Mon Mar 04, 2019 4:22 pm
Forum: HATs and other add-ons
Topic: I2C I/O PORT EXPANDER QUESTION
Replies: 37
Views: 1688

Re: I2C I/O PORT EXPANDER QUESTION

Use mcp23s17 parallel io chips instead of the mcp3208 adcs I used. My circuit ran the chips at 5v I simply used a voltage divider on miso. Fyi, 260 outputs is unusual, I suspect your application might be done differently, wiring 26 long wire will be painful and expensive. Yes, use the same idea I u...
by westwol
Sun Mar 03, 2019 11:53 pm
Forum: HATs and other add-ons
Topic: I2C I/O PORT EXPANDER QUESTION
Replies: 37
Views: 1688

Re: I2C I/O PORT EXPANDER QUESTION

Yes, use the same idea I used for adc's: https://www.mikronauts.com/raspberry-pi/raspberry-pi-analog-to-digital-conversion-experiments-and-howto/ If you connect eight MCP23017 chips on the I²C bus that gives you 128 GPIO. Connect eight MCP23S17 chips on SPI for another 128 and you still have 22 reg...
by westwol
Sun Mar 03, 2019 10:21 pm
Forum: HATs and other add-ons
Topic: I2C I/O PORT EXPANDER QUESTION
Replies: 37
Views: 1688

Re: I2C I/O PORT EXPANDER QUESTION

If you connect eight MCP23017 chips on the I²C bus that gives you 128 GPIO. Connect eight MCP23S17 chips on SPI for another 128 and you still have 22 regular GPIOs on your RPI for the rest. I've read that a Raspberry board has 2 SPI individual ports. Is there anyway to use 8x MCP23S17 on each of th...
by westwol
Sat Mar 02, 2019 9:01 pm
Forum: HATs and other add-ons
Topic: I2C I/O PORT EXPANDER QUESTION
Replies: 37
Views: 1688

I2C I/O PORT EXPANDER QUESTION

I'm working on a project where a Raspberry PI must have up to 260 outputs. So I was looking for a GPIO expander and found this chip: https://www.adafruit.com/product/732 but it only supports upto 128 I/O pins using 8 unique addresses (8 chips). Any suggestions to achieve such thing? Thanks in advance.

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