The device uses three separate L4 interconnect structures to connect peripheral modules. All L4s handle transfers with peripherals but are located in distinct power domains.
Figure 14-9 is an overview of the L4 interconnects and the peripherals attached to them.
The L4 interconnect is composed of the following interconnects:
- L4_CFG: Includes the majority of the configuration interface for L3_MAIN system modules and peripheral interconnect
- L4 PER: Includes the main peripherals that require sDMA access. L4_PER is further divided into three sub-interconnects: L4_PER1, L4_PER2 and L4_PER3. As shown in Figure 14-9, each of these L4_PERx sub-interconnects is connected to L3_MAIN initiators via three ports:
- L4_PER1_P1, L4_PER1_P2, L4_PER1_P3
- L4_PER2_P1, L4_PER2_P2, L4_PER2_P3
- L4_PER3_P1, L4_PER3_P2, L4_PER3_P3
L3_MAIN initiators access the L4_PERx peripherals through these ports. All peripherals attached to L4_PER1 are visible from all three L4_PER1 ports; this is also correct for L4_PER2 and L4_PER3. For information on which initiator can access which L4_PERx port, see Figure 14-3. - L4_WKUP: Includes peripherals attached to the WKUP power domain
The main features of the L4 interconnects are:
- Eleven ports from L3_MAIN interconnect onto 5 parallel L4 interconnects
- From one to three 32-bit initiator ports for each L4 interconnect instance (11 in total)
- 8-, 16-, or 32-bit data, single, or burst transactions
- Little-endian platform
- Non-blocking architecture with fair arbitration between masters
- Target interfaces: Fully synchronous or divided synchronous clock frequencies
- L4_CFG and L4_PER1, L4_PER2, L4_PER3 frequency equals half of L3 frequency
- Protection logic that provides user-configurable access control to targets by each initiator