Hi Richard,redhawk wrote:As far as I'm aware you can as share many i2c devices within reason but they must have different addresses.
To add to @redhawk's comment - based upon the output of i2cdetect on a Pi there are 117 available "slave addresses" however, AFAIK, many** i2c (slave) devices only have 3 address control lines leading to 8 possible unique addresses for a single device type (but some similar devices use different address sets). The other potential issue is the drive capability (or "fan out") of the i2c bus itself (especially the clock). That I'm not too sure about since I've only played around with a few devices at a time so far, but the chip datasheets should provide more detailed info.assuncao wrote:Hi Richard,redhawk wrote:As far as I'm aware you can as share many i2c devices within reason but they must have different addresses.
Thanks for your answer! It is possible to share many i2c devices... But does it depend also of the kind of device or not? I mean, I need to connect those RFID readers and they accept i2c, but could they apply any limitation about how many devices / address I can have? Thanks!
Hi,redhawk wrote:The type of device isn't important but if 2 or more share the same address line then you cannot communicate with them.
For example the TEA5767 and RDA5807M FM Radio module both use the same 0x60 I2C address.
Individually they work fine on the Pi but I cannot connect both modules together because they both use the same 0x60 address.
Thanks @Douglas6 - I missed that in the O.P.Douglas6 wrote:As far as I can see, and as you mentioned, these look like they have 6 I2C address pins, so I would expect a max of 2^6 = 64 devices on the same I2C bus, each with a unique address.
I would like to know how many devices can I connect to Raspberry Pi. I pretend to use about 12 RFID like these:
Datasheet says there are 6 bit address, but I don't know about I2C protocol, I'm asking here before to buy because it should take about a month to get here, then I have time enough to study about it.