Forum Rule: Always post complete source code & details to reproduce any issue!

Search:

Type: Posts; User: edh

Search: Search took 0.00 seconds.

  1. Replies
    5
    Views
    200

    Expanding the GPIO count

    Hi, I have experience of using multiple MCP23S107's - the SPI variant of the same chip you mention, and they work great - I currently have 7 of them hooked up to a Pi and via an ISR can reliably read...
  2. Replies
    6
    Views
    1,068

    An alternate solution would be to offload the PWM...

    An alternate solution would be to offload the PWM function to a PCA9685 16 channel 12 bit chip - these natively support phase shifting of the outputs to not only reduce total power draw but to also...
  3. Hi - I've used the SPI variant of these expanders...

    Hi - I've used the SPI variant of these expanders - MCP23S17 and they work fine on the T4 and even with sub-optimal breadboard layout I have successfully overclocked them to 18MHz. In my use-case I...
  4. Take a look at...

    Take a look at https://github.com/sumotoy/gpio_expander - I have used that library with multiple MCP23S17 GPIO expanders on a T4 using interrupts to trigger reads from 112 end points. Originally...
  5. I'd have thought that you maybe are seeing...

    I'd have thought that you maybe are seeing spikes/noise and these may be affecting the instantaneous voltage being measured at each detent.
    You could try say reading the pins 3 times in succession...
  6. Replies
    16
    Views
    572

    What a great thread - only this week was I poring...

    What a great thread - only this week was I poring through the documentation to work out how to map the physical pins to the controlling registers, particularly with respect being able to handle fast...
  7. Replies
    17
    Views
    387

    sample code to simply read GPIO expander chip with interrupt

    Hi I've attached some test code that reads up to 8 rotary encoders sitting on SPI-0 at address 0 and using interrupt pin 9 - this has been tested and works on a Due and Teensy 4.
    It merely writes...
  8. Replies
    17
    Views
    387

    If you want to interface physical rotary knobs to your software....

    Not sure if I've got the wrong end of what you are trying to solve -

    If you want to have manual pots as per your picture, you could implement them with rotary encoders and capture the digital...
Results 1 to 8 of 8