There are 2 modes in the cache. The differences are as follows:
(1) Write-back mode
For example, writing to hit cache entry is performed but writing to external RAM is not performed if the cache is hit when writing to external RAM. Writing to external RAM is performed by cache entry replace.
External RAM is written back by invalidating a specific entry or a specific address.
(2) Write-thorough mode
For example, writing to the hit cache entry and external RAM is performed if the cache is hit when writing to external RAM.