5 Replies Latest reply on Mar 13, 2018 5:20 AM by JoMe_264151

# how many i2c slave devices can be driven by a single i2c master fx2lp and fx2lp18??

how many i2c slave devices can be driven by a single i2c master fx2lp and fx2lp18??

• ###### 1. Re: how many i2c slave devices can be driven by a single i2c master fx2lp and fx2lp18??

It can support upto 128slaves. The byte that contains the address of the slave determines which slave, the data is directed to.

Regards,

• ###### 2. Re: how many i2c slave devices can be driven by a single i2c master fx2lp and fx2lp18??

A single master can drive 256 slaves?is it true practically?

• ###### 3. Re: how many i2c slave devices can be driven by a single i2c master fx2lp and fx2lp18??

Hi,

Sorry, there is a mistake in my previous response. Out of the 8 bits for addressing, one bit decides whether the i2c transfer is read or write. So it is 2^7 = 128 slaves theoretically. (I have edited my previous response from 256 to 128 to avoid confusion) But you cannot connect 128 slaves at a time practically because the load will be too much. So if you have appropriate circuitry, it is possible to connect 128 slaves.

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• ###### 4. Re: how many i2c slave devices can be driven by a single i2c master fx2lp and fx2lp18??

thank you so much,

what you mean by appropriate circuitry?

without appropriate circuitry,can we connect 8 slave devices?

what is the maximum slave devices can connect without any circuitry?

• ###### 5. Re: how many i2c slave devices can be driven by a single i2c master fx2lp and fx2lp18??

A PSoC4 GPIO can sink max. 8mA while maintaining correct voltage level. The number of I2C devices depens on the required input current and the used pull up resistor. So you need to calculate for yourself whether your 8 devices will work as required.

Bob

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