Nistune Forums

I've been handed down ALOT of documentation about the Motorola 6800 processor, to include notebooks and documentation from Motorola Conferences, original paper datasheets, and Heathkit instructional books. From reading it, an example says that the processor reads the last bit of information at the end of the ROM upon start-up to begin its instruction processing. Is this true for the processors used in the Nissan ECCS's, or do they start off somewhere else.

. . . I have noticed that the first bite of just about every binfile I have looked at begins with <OF>hex. Any correlation?

I just wanted to know so that I can know were to start dissassembling some of the data, just for fun.

the 6800 uses the last address of the 64KB space to boot from

use the following as a start to your symbol for DASMX

cpu 6802
org 0x8000

vector 0xBFF8 irq_vector int_entry
vector 0xBFFA swi_vector swi_entry
vector 0xBFFC nmi_vector nmi_entry
vector 0xBFFE res_vector reset

vector 0xFFF8 irq_vector int_entry
vector 0xFFFA swi_vector swi_entry
vector 0xFFFC nmi_vector nmi_entry
vector 0xFFFE res_vector reset

the 16KB ROM is mirrored twice in the address space at 0x8000 and 0xC000

email me and I can send you a more complete symbol table from home

I've been running the HCR32 on logic analyser and can disassemble from the trace. It shows the exact path through the code which is fantasic to work from