How fast can you write to the Flash memory chip?
The main factor is the write cycle time (tWC). Suppose that the tWC value is 60ns minimum. This means that the frequency is 16.6 MHz maximum (1/60ns). This is the speed at which you can write data into the Flash memory chip. Note that this speed is only from the Flash memory chip's point of view. When the Flash memory chip is designed into a system, you need to consider delays along the critical data path in your system. The bottom line is that the write frequency will be less than the 16.6 MHz in this example.