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fivdi / i2c-bus

I2C serial bus access with Node.js
MIT License
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What i should use as command code inside readI2cBlockSync? #5

Closed simar88 closed 9 years ago

simar88 commented 9 years ago

Hi @fivdi , i'm new about using i2c modules and i'm playing around with my new raspberry pi 2 and hover board from hoverlabs. I'm trying to translate a python library, that you can view here, in a node.js modules to use inside a project but i don't know what i have to use for this parameter. Can you say me something about it? Thanks in advance, Simone

fivdi commented 9 years ago

In general, the data sheets for I2C devices describe a register map or a command set which can be used to access the device. In reality, it's the same thing. For example, one temperature sensor could have a register called TEMP and another temperature sensor could have a command called ACCESS_TEMP. In the first sensor, the TEMP register is accessed to get the temperature. In the second sensor, the ACCESS_TEMP command is performed to get the temperature. The same thing is happening in each case.

The following Python line of code from the Hover library:

busData = bus.read_i2c_block_data(self.address,0,18)

would translate to something like this in JavaScript:

var buf = new Buffer(18);
bus.readI2cBlockSync(this.address, 0, 18, buffer);

In this case the command or register is 0, and 18 bytes of data are being read.

simar88 commented 9 years ago

Thanks @fivdi for the fast reply and for the explanation. I'll try your suggestion in these day. Thanks again! :) Simone

fivdi commented 9 years ago

No problem and good luck with Hover. I guess the issue can be closed so. Feel free to reopen if Hover can't be accessed with i2c-bus.