USB Host MSD Client Driver Instances Number. 

This constant defines the maximum number of MSD devices to be supported by this host application. For example, if 3 USB Pen Drives need to be supported, then this value should be 3. This value cannot be greater than USB_HOST_DEVICES_NUMBER, which defines the maximum number of devices to be supported in the application. If this constant is less than USB_HOST_DEVICES_NUMBER, then only USB_HOST_MSD_INSTANCES_NUMBER of MSD devices will be enumerated.

#define USB_HOST_MSD_INSTANCES_NUMBER 

None