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fivdi / i2c-bus

I2C serial bus access with Node.js
MIT License
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Laster managing I2C-bus Event ? #88

Closed yboujraf closed 4 years ago

yboujraf commented 4 years ago

Dear @imyller , @fivdi , @munyirik , @johntalton

Are you managing i2c events ?

That means if any I2C device needs to share data, automatically hte MAster will catch the information and process it ?

Best Wishes for 2020 Youssef

fivdi commented 4 years ago

@yboujraf Which type of I2C events from which type of I2C device are you referring too?

And best wishes for 2020 to you too.

fivdi commented 4 years ago

One additional question. The title of this issue is "Laster managing I2C-bus Event ?". What does "Laster" mean?

yboujraf commented 4 years ago

Dear @fivdi

I have an PCF8574 defined as GPI.

And the PCF8574 is connected to my raspberry i2c bus with many other devices.

I don't want to poll every x ms the status of each i2c equipment, I would like to be informed for each change by "on-event-change" or something like this.

Because after, my raspberry forward this information to an automation in Real time.

Same issue with A/D converter, I have a fader (10kOhms), and I need to read in real time the data but ideally by event only.

Best Regards, Youssef

fivdi commented 4 years ago

I have an PCF8574 defined as GPI.

And the PCF8574 is connected to my raspberry i2c bus with many other devices.

I don't want to poll every x ms the status of each i2c equipment, I would like to be informed for each change by "on-event-change" or something like this.

Page 11 of the PCF8574 datasheet states the following:

It should be possible to connect the open-drain INT output of the PCF8574 to a GPIO on a Raspberry Pi and detect the interrupts using the onoff module. The onoff watch method can detect hardware interrupts without polling. Note that the INT output on the PCF8574 is an open-drain output so a pull-up resistor will be needed. For an example of a Node.js I2C device driver that detects interrupts triggered by an I2C device take a look at mcp9808-temperature-sensor. An MCP9808 temperature sensor has an open-drain Alert output that serves a similar purpose as the open-drain INT output of the PCF8574. Keep the watch handler as short as possible to avoid missing interrupts.

Same issue with A/D converter, I have a fader (10kOhms), and I need to read in real time the data but ideally by event only.

You'll need to look at the datasheet to see if the device supports interrupts.

fivdi commented 4 years ago

I think the required information has been provided so I'll go ahead and close this issue.

yboujraf commented 4 years ago

Thanks You are a great man.