looks like I got M58846 dumping now. The bit order isn't 100% sure but it does look rather good. The initialization code appears to be 100% correct.
I found that the code uses 4 undefined opcodes- 008h, 009h, 018h, and 019h. There's plenty of others but only those show up. I found that the M58845 uses them for the ADC so I added them for that but they don't really make much sense. After tracing through the VFD update code, I'm 99% sure 018h is a left rotate or acc=acc+acc. (which is the same thing) The code here illustrates that:
Code
01-00 005 EI ;external interrupt vector
01-01 046 RTI
01-02 041 LCPS 1 ;timer 1 interrupt vector
01-03 01A TEAB ;move AB into E
01-04 0CC LXY C ;point to RAM 0ch
01-05 064 TAM 0 ;get memory in 0Ch (grid #)
01-06 00C TYA ;old grid
01-07 014 RD ;turn off old grid
01-08 002 INY ;next grid #
01-09 03C SEY #C ;is it 12? (there's 12 grids)
01-0A 1A5 B 25 ;no
01-0B 0EC LXY C ;address 0ch
01-0C 021 SZB 1 ;do we read buttons?
01-0D 1A0 B 20 ;do not read buttons
01-0E 0B1 LA #1 ;check left+down buttons
01-0F 081 OFA ;acc to port F
01-10 04D SB 1 ;we read buttons
;buttons are on bits 0 and 1 of K port which is loaded into A
;via the IAK instruction. bit 2 isn't used and bit 3 is skill.
01-11 0CD LXY D ;L+D buttons go into 0dh
01-12 057 IAK ;read button register
01-13 060 XAM 0 ;store in RAM
01-14 0B2 LA #2 ;check up+right buttons
01-15 081 OFA ;acc to port F
01-16 05F RB 3 ;clear bits 2/3 of 0dh
01-17 05E RB 2
01-18 048 RC ;clear carry
01-19 057 IAK ;read button register
01-1A 018 *XAL ;shift left I think
01-1B 048 RC ;clear carry
01-1C 018 *XAL ;shift left I think
01-1D 00A AM ;add DL00 to 00RU in RAM 0dh
01-1E 060 XAM 0 ;store into 0dh (DLRU buttons)
01-1F 1A4 B 24 ;done
01-20 0E8 LXY 8 ;if we do not read buttons
01-21 000 NOP ;waste time instead
01-22 002 INY
01-23 1A2 B 22 ;loop
01-24 0C0 LXY 0 ;fall thru (if grid = 12 sets to 0)
01-25 065 TAM 1 ;get data at addr 0Y
01-26 01C TBA ;put it into B
01-27 067 TAM 3 ;get data at addr 1Y
01-28 01B OSAB ;put it into A then output to port S
01-29 065 TAM 1 ;get data at addr 2Y
01-2A 084 OGA ;output it to port G
01-2B 064 TAM 0 ;get data at addr 3Y
01-2C 081 OFA ;output it to port F
01-2D 015 SD ;turn on grid Y (new grid)
01-2E 01D TAY ;grid # into Y
01-2F 0CC LXY C ;point to 0ch
01-30 060 XAM 0 ;store grid # into 0ch
