• The x-axis represents masters, and the y-axis represents slaves.
  • A microcontroller will have at least one master - the processor. In this case, it is ARM Cortex-M4.
  • It may have several other masters as well, e.g. Ethernet, USB2.0, DMA.
  • The dots in the grid indicate, broadly, the busses each master can use to communicate with each slave.
    • For example, the bus matrix allows the processor to use the D-bus to communicate with three slaves: flash memory (through D-code), SRAM1, and FMC external.
    • In accordance with what we expect, the I-bus can only interface with I-code, the D-bus can only interface with D-code, all of which connect to flash memory. This privilege is not granted to S-bus.
  • Note that specific privileges and configurations vary between bus matrices for different boards!