6800 opcode $02

I pulled this off of the web by googling. no way to verify it. this was the website, for credit's sake http://neil.franklin.ch/Usenet/alt.folklore.computers/19971216_HCF ... It was the 6800 that had such an instruction. It was a variant of the 'JMP' (jump) instruction that "jumped to the accumulator". The opcodes are 0x4E and 0x5E (for the A and B registers respectively). While not used in "normal" operations, they are convient for bringing up new designs. One could wire the data buss to either of the codes, and reset the processor. Upon reset, the processor reads out locations 0xFFFE and 0xFFFF for the location of the first instruction to execute (it gets 0x4E 0x4E), then it sets the address buss to that location and reads an instruction from there, getting 0x4E. This causes the address buss to increment and cycle thru, reading every location on the buss. With a scope, properly attached, quite helpful. Shows up decodes and the like for the various I/O, RAM, ROM devices. Might even show up conflicts, or a mal formed decode PAL.