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I²C connection with RFID

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#1 FVN.Net



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Posted 03 October 2012 - 07:06 PM

I made a new topic to abandon the old (here) since I feel I made some progress.

I tried to write 'native' VB code for my I²C connection, so not using any custom class or wrapper like the Toolbox. Here's what I came up with:

Dim outbytes() As Byte = New Byte() {}
Dim inbytes(6) As Byte '= New Byte() {}

Dim cfg As New I2CDevice.Configuration(80, 400)
Dim iic As New I2CDevice(cfg)

outbytes = New Byte() {160, 1, 1}

Dim write_transaction As I2CDevice.I2CTransaction = I2CDevice.CreateWriteTransaction(outbytes)
Dim read_transaction As I2CDevice.I2CTransaction = I2CDevice.CreateReadTransaction(inbytes)
Dim transActionList As I2CDevice.I2CTransaction() = New I2CDevice.I2CTransaction() {write_transaction, read_transaction}

Dim i As Integer = iic.Execute(transActionList, 5000)

The good thing is: this code does NOT result in an error. It seems the array that will contain the read bytes should have a fixed size. That makes sense, in retrospect. So after defining the size of this array, the exception was gone.

The bad thing is: the inbytes array is not filled with valid data but stays filled with zeroes.
FWIW, the device I'm trying to interface with is here (RFID reader).

EDIT after 2 hours of more testing and trying.
This line of code:
Dim i As Integer = iic.Execute(transActionList, 1000)[/code]

returns 1 WITH 10k or 2k2 pull ups
returns 3 WITHOUT these pull ups.
I'd say 3 is correct because of 3 items in outbytes. The inbytes array does not change, unfortunately.

Any clues?
- Franki

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