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.
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.
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.
