The device memory hierarchy includes four levels:
- L1 is internal to the CPUs. It concerns data exchange with the internal Level1 cache memory subsystem, and it is the closest memory to the microprocessor unit (MPU) core and the IVA core.
- L2 is included in the IPU subsystem and the MPU subsystem.
- The chip-level interconnect consists of one L3 interconnect and five L4 interconnects. It enables communication among the modules and subsystems in the device.
Figure 14-1 shows an overview of the L3 and L4 interconnect architecture.
Note: ATL, VCP1, VCP2, MLB and USB3 (ULPI) are not supported on the AM571x / AM570x family of devices.
SATA and RTC are not supported on the AM570x family of devices.
Furthermore, for AM570x the supported set of features and peripherals is device part number dependent. Refer to device Data Manual, for more information.
- L3 handles many types of data transfers, especially exchanges with system-on-chip/external memories. L3 transfers data with a maximum width of 128 bits from the initiator to the target. The L3 interconnect is a little-endian platform
- The L4 is composed of the following:
- L4_CFG: Includes the majority of the firewall configuration interface for level 3 (L3) system modules and peripheral interconnect;
- L4_PER: Includes the main peripherals that
require system direct memory access (sDMA) access. L4_PER has three
instances L4_PER1, L4_PER2 and L4_PER3. Each of these three instances
has three ports connecting it to L3_MAIN interconnect:
- 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.
Through the L3_MAIN interconnect, different initiators can access
each of these L4_PERx_Pi ports. For information regarding which
L4_PERx_Pi port each initiator accesses, see . - L4_WKUP: Includes peripherals attached to the WKUP power domain.
Modules are connected to the interconnect through
an IA for the initiator module and a TA for target modules. Each module/subsystem
connection is statically configured to tune the access, depending on the
characteristics of the module.
To unauthorize a module or L4 interconnect access, some TAs include configurable firewalls (FWs). A firewall restricts or filters the accesses allowed to an initiator according to different access criteria. The firewalls can usually be configured by software.
The L3 and L4 interconnect default settings are
fully functional; they enable all possible functional data paths and a minimal
default protection setting.