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In microprocesser mode, the 5402 places its interrupt vector table in external memory. Since external memory is very slow, I am considering relocting the interrupt vectors to internal DARAM. The documantation mentioned that this can be done by setting the IPTR bits in the PMST register. The IPTR field has 9 bits, and it should contain the address of any 128-word page in program mem space. By default, the interrupt vectors are located from 0xFF80 to 0xFFFF. Thus, the IPTR's reset value, (1111 1111 1)b, represents the 128 word page beginning at 0xFF80. To relocate the vector, I can change it to 0x3FE0. After the PMST register is loaded, the DSP will look at 0x3FE0 to 0x3FFF for interrupt vectors. If I am using DSP/BIOS, should I change the PMST register at main, or after the BIOS modules are loaded. Also, Is there any other thing I need to do besides copying the contents in (0xFF80 - 0xFFFF) to (0x3FE0 to 0x3FFF)? Any help or comment is appreciated. |