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fivdi / i2c-bus

I2C serial bus access with Node.js
MIT License
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deviceId throws exceptions for known active address #76

Closed dkebler closed 5 years ago

dkebler commented 5 years ago

deviceId seems a new? available method so I decided to try it.

Just wondering if this method/function is only supported if the device itself supports it as when I try it for an existing device address (obtained via scan). The returned callback error is

Remote I/O error

Not sure waht Remote means but maybe it refers to the i2c device being queried? So maybe I/O error just means the chip(mcp23008) doesn't support this function? Maybe this is a newer i2c standard that device manufacturers are supposed to support? I see nothing in the mcp23008 data sheet on this.

dkebler commented 5 years ago

I see that error is number 121 which is a linux #define EREMOTEIO 121 /* Remote I/O error */ I kinda assumed this was an error you threw in the C code Maybe the I/O refers to reading a sys file which is supposed to have that device info in it and doesn't because the device doesn't support it?

fivdi commented 5 years ago

deviceId seems a new? available method so I decided to try it.

It's fairly new. As mentioned in History.md deviceId was added with i2c-bus@3.2.0.

Just wondering if this method/function is only supported if the device itself supports it as when I try it for an existing device address (obtained via scan). The returned callback error is

Remote I/O error

deviceId will only work if the I2C device supports it. For further information please take a look at the datasheet for the I2C device in question. Devices are not required to support deviceId.

The Remote I/O error comes from the I2C device driver. It this case the driver will have asked the I2C device to sends its deviceId but the device did not respond to the decide driver.

This isn't a problem with i2c-bus so I'll go ahead and close this issue.