2.2.1. Regions

A region is a contiguous area of address space. The TZASC provides each region with a programmable security permissions field. The security permissions value is used to enable the TZASC to either accept or deny a transaction access to that region. The transactions arprots[2:0] or awprots[2:0] signals are used to determine the security settings of that transaction.

The TZASC always provides two regions, region 0 and region 1, and you can configure it to provide additional regions. With the exception of region 0, the TZASC enables you to program the following operating parameters for each region:


Region 0 is known as the background region because it occupies the total memory space. You can program the security permissions of region 0, but the following parameters are fixed:

Base address



The AXI_ADDRESS_MSB configuration parameter controls the address range of the TZASC, and therefore the region size.

Subregion disable

This feature is not available for region 0.

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