Can someone point out the adress of the rev limiters in the algorithim for $6E to me? I've looked over my hac a couple times and either it isn't labeled or my eyes hurt from staring at code for so long. Probably the second one LOL.

 

Search in the hac for LC3AF (Threshold value for cut off)
Just below LFA6E
Starting at the LDX command, If higher than C3AF...
Set bit L0044,#0x40 (Set fuel cut off flag)
Its labeled "Speed Limiter" that is for MPH,

The RPM limiter is C3B0 & C3B1 (double word 16 bit)
It is not directly called but is "indexed" addresesed by this line right below the speed limiter.
First checks MPH, then checks RPM.

Jp

 

Well it kinda works. When it hits the limit there's a loud backfire & spark's cut for a sec but adds spark back in and continues to rev for a sec or 2 then another backfire & cut. What I did was change the instruction at LFA96 to jump to the knock retard routine. I also tried the low rpm spark routine at LD23A and had pretty much the same results, just a louder backfire LOL. Need to find a way to keep spark cut.

 

It works! But only in gear . I directed it to the hot restart rotine at LCF3B and set hot restart retard to 60*. Does what I want in gear but it can still overrev in neutral... still need to tweak it some. Also stays in hot restart spark until closed loop. GRRR.

 

Looks like I should've changed the adress at LFAAB to LCF3B instead of all this other stuff I did. I misinterprited the code, which explains why it ran like it was stuck in antistall after it hit the rev limiter. Can someone explain what subroutine this command jumps to???

FAB5: LFAB5 JSR 0,X

 

I believe I get the indexing and can render a bit o' help.

The command is stating to go to the "Address" indexed at the "zero" position from the previous "X" stored address.

Just above you will see there are a couple of LDX commands that are followed by "#" L**** with address values.
This loads the "Value" or address into the X register.
From there the index command says how far from that starting point to go.
Being this is zero indexed, it would be the actual address value "previously" loaded into X.
Not knowing exactly where you jumped into the code from can lead you into a couple directions.
You will probably need to go backwards up through each of the above lines to see where you "may" have come from.

From a quicky glance (because I'm not terribly familiar with the 6E)
It appears it may go to the AE routine #LFB27 if you came in before LFAAF: (again depends on the bits)
It will go to #LFB3E after LFAAF:

FA6C: lable is where that section begins, finding what the bits at L003F and L0039 do should give the definite answer.
HTH

 

Hmm, ok here's the changes I'm going to try next. Getting rid of hot start spark altogether frees up some space as well. Hopefully this will do it without any unseen side effects.

CF20: BRSET L0001,#$04,LCF38 ; Branch to LCF38 if rev limiter bit set
; ... else
CF24: JSR LCF3E ; Jump to LCF3E
(Clear everything to LCF38)

CF38: LCF38 LDAB LC02A ; Load Hot Restart Retard
CF3B: BCLR L0001,#$04 ; Clear b2 spark retard rev limiter



FAAA: BSET L0001,#$04 ; Set b2 spark retard rev limiter
FAAD: BRA LFAB7

 

Well that didn't work right either. Runs great until startup enrich decays out then sputters and dies... still tracking down what else I need to change.

 

Got it! Still need to figure out an issue with accel enrichment but otherwise it's doing exactly what it should. Just needed to correct the instruction here.

CF24: BRA LCF3B ; Branch to LCF3B

 

Not to hijack, but what are the advantages/disadvantages of spark cut vs fuel cut for a rev limiter?

 

A spark cut rev-limiter allows you to blow up the mufflers...

Although what I think bl85c is trying to do is to retard the timing which will reduce the power output of the engine.

RBob.

 

LOL, no explosions here. Not yet anyway. Fuel cut with the nitrous going = boom, spark cut's much better.

It's really a spark retard rev limiter because I can't actually turn off the module. Even if the ecm doesn't command it the coil will still fire at base timing. This probably won't work with distributors either because they're mechanically limited to something like 5* of total retard. I'm finding out that you need to whack alot of timing out at wot to really kill the power at higher speed.

 

Flamethrower Code!

 

Can someone explain the difference between branch if carry set and branch low? They both look like the same command in hex.

 

The "carry" bit is set when a calculation exceeds the maximum value (space for 8 bit = 255, 16 bit = 511)
Branch will occur then.
Text from "BVS" (Encoded 29 command)
Test the state of the V bit in the CCR and causes a branch if V is set.
Used after an operation on twos-complements binaries values, this instruction will cause a branch if there was an overflow. That is, branch if the twos-complements result was invalid.

Basically, Branch if "Accumulator Value" is Less than "Memory Value"
Text from "BLO" (Encoded 25 command)
If the BLO instruction is executed immediately after execution of any of the instructions CBA, CMP(A,B or D), CP(X or Y), SBA, SUB(A,B or D), the branch will occur if and only if the twos-complement number represented by the ACCx was less than the twos-complement number represented by M. Generally not useful after INC/DEC, LD/ST, TST/CLR/COM because the instructions do not affect the C bit in the CCR.

 

Here is a quick list of functions from member "TheGreatJ" that is useful.
Has the machine codes for each command too.

 

how is the file inside the ZIP to be used? no extension, so i open it with notepad and it's all greek to me...

 

It was a DOC file until I zipped it ???
Throw an RTF or DOC extension on it and see if it will come to life.
If not I'll convert it to plain text and re-up it.

 

tried DOC and RTF... as a RTF, it shows craziness, and i can't even open it as a DOC..

 

serching through my files for another copy...
Didn't find that file but I did find this one. Printed to PDF so you can open it easier. Has more info than the one above but is a bit more confusing.
Will have to post the original tomorrow from work where the file is at.

 

Here is the file contained in the zip above.

 

that's readable. confusing as hell to me, but at least it's in english.

 

The thing to look at when going through the code is the "Opcode" for the command.
It can indicate what type of addressing was used with that command.
It helps when doing the assembly/disassembly to have the Opcodes shown in the .DIS or .LST files too.

 

*blank stare*

*blinks a few times*

trust me, even that was above and beyond my current understanding....

 

LOL, that's how I feel. It's still greek but once you start to memorize the commands you can see what does what. Just need to experiment and read through the hack to see how gm programmed things.

 

I'm going to move this hack somewhere else because I found a better use for the hot restart routine. I want it to go into the hot restart routine in power enrich so load changes won't affect wot spark. I end up with more spark than I want when I hit the nitrous because the calc'd load drops. I'm also going to add a speed qualifier for the hot restart retard to help with launch traction. What section actually limits spark to the far side of the main table though?

;
; HOT RE-START RETARD
;
CF20: LDAA L0001
CF22: BITA #$20
CF24: BNE LCF34 ; BR IF b5, (if IAC kick dn enab)
; ... else

CF26: LDAB L0060 ; LOAD START UP COOLANT
CF28: CMPB LC029 ; Compare to Low Lmt for Hot Restart
CF2B: BLO LCF34 ; Branch If Lower

CF2D: LDAB L001A ; Load Eng Run Time
CF2F: SUBB LC57B ; Subtract Min Eng Runtime
CF32: BLO LCF3B ; Branch If Lower

CF34: LCF34 CLRB
CF35: ORAA #$20 ; SET b5 Condition, IAC KICK DN ENABLE FLG
CF37: STAA L0001
CF39: BRA LCF3E


CF3B: LCF3B LDAB LC02A ; Load Hot Restart Retard
CF3E: LCF3E LDAA L003B ; HU DISPLAY MD WD
CF40: ANDA #$DF
CF42: STAB L0457 ; HU DISPLAY MD WD
CF45: PSHB
CF46: BEQ LCF4A

CF48: ORAA #$20
CF4A: LCF4A STAA L003B ; HU DISPLAY MD WD
CF4C: CLRA