I2C controller without sensor.
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- yzfoot
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I2C controller without sensor.
Searching for a standalone I2C controller but not finding. . I understand there are copious sensors of all sort with I2C connections but that is not what I want. I want an I2C interface that I can add my own devices to. Is there not such a chip ? I look at I2C devices I have and don't see such a chip. Is that function accomplished some other way ? Enlightenment of any sort appreciated.
- adafruit_support_bill
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Re: I2C controller without sensor.
It depends on what you want to control. We use the PCA9685 as an i2c interface/control chip for many of our DC/Stepper motor control boards. The PWM outputs of the PCA9685 are used to control the dual H-Bridge motor driver chips.
The MCP23017 is used as an i2c interface/control chip for our character LCD boards.
If your devices have analog interfaces, you can use an i2c ADC/DAC like the PCF8591.
The MCP23017 is used as an i2c interface/control chip for our character LCD boards.
If your devices have analog interfaces, you can use an i2c ADC/DAC like the PCF8591.
- adafruit_support_carter
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Re: I2C controller without sensor.
I2C is generally a (very common) peripheral of the microcontroller. What devices are you working with?
What does "own devices" refer to here?I want an I2C interface that I can add my own devices to.
- dastels
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Re: I2C controller without sensor.
I2C support is generally incorporated into microcontrollers.
There are chips to add I2C capabilities to CPUs/MCUs that don't contain an I2C interface. E.g. https://www.nxp.com/products/interfaces ... er:PCF8584.
Dave
There are chips to add I2C capabilities to CPUs/MCUs that don't contain an I2C interface. E.g. https://www.nxp.com/products/interfaces ... er:PCF8584.
Dave
- yzfoot
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Re: I2C controller without sensor.
I don't want to add I2C to an MCU that doesn't have it, found a chip that does that. I want to connect a micro controller that has I2C to this new device that provides I2C connectivity. On the other side of that new device is/are my "own devices". Currently I'd like that to be a small bank of user input switches, in the future maybe the digital side of an ADC, or who knows what might be desired later. The key is I2C connectivity with whatever the market doesn't then provide as a sensor. I know many many things now provide I2C connectivity, probably even those that I called out but not everything imaginable so one might want to 'roll their own' and when that comes up I'd like to be prepared.
- dastels
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Re: I2C controller without sensor.
AH. In that case I'll second Bill and suggest the MCP23017: 2 8-bit digital port, each bit can be input or output with option pullups.
I've used it A LOT. E.g. https://learn.adafruit.com/digital-circ ... m-emulator That's the only published project.
Another approach is SeeSaw https://learn.adafruit.com/adafruit-see ... 9-breakout, which is a configurable I2C interface.
Dave
I've used it A LOT. E.g. https://learn.adafruit.com/digital-circ ... m-emulator That's the only published project.
Another approach is SeeSaw https://learn.adafruit.com/adafruit-see ... 9-breakout, which is a configurable I2C interface.
Dave
- yzfoot
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Re: I2C controller without sensor.
I looked at the PCA9685, seems the controllable pins are all outputs, filed for later.
MCP23017 Looks promising !
PCF8591 Looks good for analog only use
Thanks for the info, I think this is what I was looking for, very much appreciated.
MCP23017 Looks promising !
PCF8591 Looks good for analog only use
Thanks for the info, I think this is what I was looking for, very much appreciated.
- yzfoot
- Posts: 77
- Joined: Wed Dec 08, 2021 6:02 pm
Re: I2C controller without sensor.
MCP23008 on order due tomorrow. While waiting I looked more at your seesaw device, that's pretty much what I had envisioned when I started this search. I see in the docs references to both the SAMD09 and ATTiny8x7 micro controllers. Is the seesaw available with my choice of micro controllers ? I also notice the docs are from 2017. Maybe thing have evolved.
- dastels
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Re: I2C controller without sensor.
I'm not sure about that, but it *is* a nice platform, and the firmware is easy enough to customize... mostly just fiddling with the config file.
Dave
Dave
- adafruit_support_carter
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Re: I2C controller without sensor.
The SAMD09 based seesaw was the original - along with a few other SAMD variants. The ATTiny8x7 seesaw is newer and created due to supply issues obtaining SAMD processors. But the ATTiny8x7 was written to the original c2017 SAMD seesaw spec.
- yzfoot
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- Joined: Wed Dec 08, 2021 6:02 pm
Re: I2C controller without sensor.
Thanks again. Informative as usual from Adafriut !
Please be positive and constructive with your questions and comments.