AM1808 On-Chip ROM and RAM

Zheng Zhao said:

Although the space is reserved for vector table, can I put other code into this area? It seems that this can be done by configuring in the linker.cmd file. Is it allowed? Has anyone ever tried this?

Yes you can put other code/data in this ARM RAM area. It will work and is a supported use-case. FYI linux also does not use the ARM local RAM for vector table. Since MMU is on, Linux just uses a page (4K byte) in external RAM for this purpose and maps it to the address 0xffff 0000

Zheng Zhao said:

How fast is this ROM comparing with 8KB RAM? How about comparing with the 128KB L2 RAM?

And how could data be written into this ROM area? Is any physical device required (for like burning)?

We don't have much data on ROM performance, additional the ROM area is not use-able by customers. It contains the TI ROM Bootloader , and does not support any custom programmation outside TI.

The L2 RAM which is more commonly known as Shared RAM in the documentation (it is L2 for ARM only devices like AM18x but L3 for DSP for ARM+DSP devices) , there is some data available on basic read/write performance. You can find this logged here

http://processors.wiki.ti.com/index.php/Shared_RAM_Access_Considerations_on_OMAPL1x/C674x/AM1x

Regards

Mukul