SC16IS750 oscillator enable with GPIO

[robin_ptl]

Hi,

I'm looking to use an SC16IS750 device in a design along with a crystal oscillator to provide a clock for the UART section of the SC16IS750.  The crystal oscillator has a undesirably high current consumption for my application, so I was proposing to control the EN pin on the oscillator via one of the GPIO pins on the SC16IS750 device, so it can be powered down when not in use.

My question (possibly more a confirmation) is this:  Can the host MCU control the GPIO of the SC16IS750, without the SC16IS750's oscillator running?

My understanding from the datasheet is that the oscillator is only required for the UART transmitter and receiver.

"Once the device is reset properly, the host processor can start to communicate with the device. Internal registers can be accessed (read and write), however, at this time the UART transmitter and receiver cannot be used until there is a stable clock at XTAL1 pin. "

Thanks,

Robin

[TomasVaverka · Accepted solution]

Hi Robin,

You are right, the internal registers of this device can be accessed, hence, GPIO pins configured and controlled without the crystal oscillator.

Best regards,

Tomas