Dear team
What is the clock frequency of SPI interface. could you help to recommend?
Many thanks
Denny
Hello Denny,
For a quick rule of thumb answer that completely ignores their system, it should be no faster than 7.8MHz. The typical value for most of our GUIs is around 1MHz
With that being said, the real answer is to understand a couple of choices for their system and compare it with the appropriate table in the datasheet. The first choice is to know what interface mode they are using by looking at the state of the M0 pin (IOVDD: Asynchronous interrupt mode GND: Synchronous master controller mode No connection: Synchronous slave target mode; use for multi-device mode). The second is to know what IOVDD voltage they are using (1.65 V ≤ IOVDD ≤ 2.7 V vs. 2.7 V < IOVDD ≤ 3.6 V). And finally, they need to know if there are multiple devices on the same SPI line or not.
For example, if I have a system that uses 1.8V for the IOVDD, just one device on the SPI line, and is in synchronous target mode, I can go to the respective table in the datasheet and look for the corresponding t_c(SC) spec.
In this case it is 2*t_CLKIN which has to be >2*64ns or <7.8MHz in context of the timing spec. This is further supported by the f_CLKIN spec which shows that it cannot exceed 15.6MHz or ~64ns period, which would translate to the same 2*64ns or 7.8MHz.
Other modes might not list the t_CLKIN as a dependency but directly show the value.
Best,
-Cole
