11.6.7 Tightly Coupled Memory

Users can use a part of the cache as Tightly Coupled Memory (TCM). The Cache Size Configuration determines the cache size by Software bits in the Cache Configuration register (CFG.CSIZESW). The relation between cache and TCM is as given below:

TCM size = (Maximum cache size - Configured cache size)

The user can obtain the TCM start address from the product memory mapping. The cache memory starts first from the address followed by the TCM memory. Size of the Way is fixed and the number of ways varies according to the available size for the cache memory. See Product Memory Mapping Overview from Related Links.

Table 11-1. TCM Sizes
Maximum Cache Configured CacheTCM Size
4 KB4 KB0 KB
4 KB2 KB2 KB
4 KB1 KB3 KB
4 KB0 KB4 KB

The TCM is also accessible in its maximum size in case of disabling the CMCC. The TCM does not need to be locked to operate.

Note: Writing into the cache DATA RAM region through the CPU can overwrite the valid cache lines. This can result in data corruption when the cache controller is accessing the data for cache transactions. Access the DATA RAM region only after configuring it as TCM.