Different methods of reading and writing using cache have been developed. Some of those are described here.
Reading Using Cache
CPU request memory from the cache. Only if the data is not present is the main memory queried.
CPU requests memory from cache and main memory simultaneously. If the data is in the cache then it is returned, otherwise the CPU waits for the data from the main memory.
Writing Using Cache
Write Through Cache
When data is stored back to memory it is written to cache and main memory at the same time.
Data in the cache is compared to the data in the main memory. Data is written only if there is a difference.