Good day.
I am reading the reference manual for the Cortex-M4 processor and I see that this processor uses the AMBA AHB-Lite 3 bus architecture version. I open the AMBA AHB-Lite 3 specification and do not see a description of the MEMATTR signals, which the processor uses to encode information about the memory type when accessing it - normal, device, or strictly ordered. Why is there no description of these signals in the specification? If these are "out-of-band" signals, then I do not see in the AMBA AHB-Lite 3 description the admissibility of expanding the bus signals (maybe I did not look carefully?).