I have to connect 12 in Nos PCA9554 to read data on its input i/o at 400KHz SCL frequency. all is well till 2 PCA9554 are connected. The moment a 3rd slave I2C ic is connected, SCL is stuck at low from +5V. I have used a pull up resistor of 10K. Is it too high or too low. PCA9554 data sheet shows a 10K in its drawing, but for one IC. Reduced SCL to 320 KHz but no use. SCL stuck low and micro-controller hangs.
I load Command 0x00 (read command) on start up to all PCA9554 individually. Later when data is to be retrieved, START with Address+read followed be NAK to individual PCA9554 and finally a STOP.
OK till 2 ICs, but on 3rd, the controller hangs with SCL stuck at low.
The whole exercise was done successfully with 12 nos PCF8574 but data retrieval rate was not sufficient.
Solution please. Awaiting.