CCR and LDAx
12-24-2005, 05:38 PM
#1
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CCR & the IAC
Code:
;///////////////////////////////////////////////////////////////////
AXCN IAC stuff
AXCN addresses before ;
LE72E: ldab L0111 ; REQUESTED IAC MOTOR STEPS
lslb ; mult x 2 to set z & c flag
beq LE781 ; br to ck b3 IAC MW L00FD, START UP DELAY DONE- if req'd IAC is zero or >=128
; else ^(br LE769: in AUJP)^
dec L0111 ; REQUESTED IAC MOTOR STEPS (-1)
******** Diff from here down in AUJP- code added from axcn******************
ldab *L002B ; CURRENT IAC POSITION (carry flag unchanged)
bcc LE753 ; br if carry flag clear from lslb (true if accb was 1 to 127)
; else
brclr *L003A,#0x10,LE748 - bit 4 IAC pos has changed bit
brset *L003A,#0x20,LE748 - bit 5 IAC pos is decreasing???
inc L0111 ; REQUESTED IAC MOTOR STEPS +1
bra LE7A8 ; go do base bias calc (br LE790: in AUJP)
LE748: beq LE74B ; br if CURRENT IAC POSITION =z?? (br LE746: in AUJP)
; else
decb ; dec L002B Curr IAC pos
LE74B: dec L011A ; IAC RUNNING COUNTER (-1)
bset *L003A,#0x20 ; set b5 IAC pos is decreasing
bra LE76C ; go store curr iac pos
LE753: brclr *L003A,#0x10,LE760 ; br if not b4 IAC pos has changed bit
brclr *L003A,#0x20,LE760 ; br if not b5 IAC pos is decreasing???
; else
inc L0111 ; REQUESTED IAC MOTOR STEPS +1
bra LE7A8 ; go back & calc IAC adj value (br LE790 in AUJP)
LE760: cmpb 0x42,x ; L866A: 0xA0 ;=160, MAX STEP MOTOR POSIT POSSIBLE (x=8628)
bcc LE781 ; br if CURRENT IAC POSITION >= L866A to check b3 of (PID),(IAC),(A/C) MODE WORD 1
; (br LE769: in AUJP)
; else
incb ; L002B curr IAC pos +1
inc L011A ; IAC RUNNING COUNTER +1
bclr *L003A,#0x20 ; clear b5 IAC pos is decreasing???
** Same as AUJP here on until.. ************
clc ; clear carry flag
LE76C: stab *L002B ; CURRENT IAC POSITION
;///////////////////////////////////////////////////////////////////
LE7D8: tba
LE7D9: staa L0120 ; IAC ADJUSTMENT VALUE ???? (This is LE7C1: in AUJP)
******** Diff from here down in AUJP- code added ******************
LE7DC: bclr *L003A,#0x10 ; clear b4 IAC pos has changed bit, br to here if no move??
ldab *L002B ; CURRENT IAC POSITION
cmpb L01C2 ; old IAC position from this calc?
beq LE7E9 ; br if no change in curr IAC pos
; else
bset *L003A,#0x10 ; set b4 IAC pos has changed bit
LE7E9: stab L01C2 ; store curr IAC as old iac position
** Same as AUJP here on until till end ************
brclr *L00C0,#0x40,LE813
brset *L0048,#0x02,LE800
;///////////////////////////////////////////////////////////////////
AXYC code diff with AXCN
AXYC has the following added
;-------------------------
;Initialize Vss
;-------------------------
ldaa #0x27 ; VAL = 39, MAX FOR NO RD SPD Ctr
staa *L0084 ; ROAD SPEED NO PULSE COUNTER
;-------------------------
;Initialize IAC posit
;-------------------------
*************** from here down in AUJP- code added from axyc ******************
ldaa *L002D ; KEEP ALIVE MIN MOTOR STEPS
cmpa L869D ; .byte 0x46 ;= 70, MAX KEEP ALIVE MOTOR STEPS
bhi LB1E2 ; br if KA > max & set ram fail bit
cmpa L869C ; 0x0A ;= 10, MIN KEEP ALIVE MOTOR STEPS 20d in AXYC
bcc LB1EA ; br if KA >= min
; else set ram fail bit and use default KA steps
LB1E2: bset *L003E,#0x40 ; Air MW b6, 1= RAM FAIL
ldaa L8699 ; 0x28 ;= 40, DEFAULT KEEP ALIVE MOTOR STEPS
staa *L002D ; KEEP ALIVE MIN MOTOR STEPS
********* Same as AUJP here on until end when including AXCN diffs ************
LB1EA: ldaa L8629 ; COLD IAC PARK POSIT
adda *L002D ; KEEP ALIVE MIN MOTOR STEPS Or is it for the BCC at the end? -See bold-
Last edited by Z69; 12-25-2005 at 01:00 PM.
12-24-2005, 08:37 PM
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Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
You are correct in that the BEQ will occur if the requested IAC steps are equal to zero. This is set during the Logical Shift Left operation if the requested steps are equal to zero.
Edit: Oops. Got that all wrong the first time!
Edit: Oops. Got that all wrong the first time!
Last edited by dimented24x7; 12-24-2005 at 08:41 PM.
12-24-2005, 08:45 PM
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Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
From whats shown, basically it looks like a really round-about way of checking if the IAC steps have been decayed out. Threw me off the first time because its sort of a strange way of doing it. Although the contents of B are probably used further down, so it probably makes more sense as a whole.
12-24-2005, 08:49 PM
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Car: 88 Camaro SC
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Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Oh, the bra if carry clear will happen if the IAC steps in L0111 are less than 128. In this case its proabably used to check for and handle an overflow further down or something. This is set when the LSL occurs.
Last edited by dimented24x7; 12-24-2005 at 08:53 PM.
12-24-2005, 09:28 PM
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Car: check
Engine: check
Transmission: check
The value in L0111 is a request to move the IAC n steps. Bit 7 of L0111 defines the direction to move the IAC: retract or extend.
The LSLB is to move b7 out and set/clear the Z flag based on the remaining bits. The BEQ then being ' no IAC movement requested.'
RBob.
The LSLB is to move b7 out and set/clear the Z flag based on the remaining bits. The BEQ then being ' no IAC movement requested.'
RBob.
12-25-2005, 07:56 AM
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Car: check
Engine: check
Transmission: check
Originally posted by dimented24x7
Ah, makes more sense now. So the term in L0111 is signed then.
Ah, makes more sense now. So the term in L0111 is signed then.
RBob.
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12-25-2005, 12:07 PM
#8
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-edit code above-
I can see why the AXYC code snip is added. AXCN & AUJP don't have it. Looks like a fix for some reported problem to GM.
But I can't tell what added benefit the AXCN code listed has for an MT.
AXYC(305 MT) has the same code snip too.
I can see why the AXYC code snip is added. AXCN & AUJP don't have it. Looks like a fix for some reported problem to GM.
But I can't tell what added benefit the AXCN code listed has for an MT.
AXYC(305 MT) has the same code snip too.
12-25-2005, 12:35 PM
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Ok, I took a closer look at it...
First time Ive ever looked at the 8D before and I got the wrong impression. My mistake.
Thats sort of a wacky way to do it. From what Ive seen so far, in the later PCMs the entire routine is based on airflow to make the proportional, integral, and derivative terms' action linear and at the end a lookup is done to translate the airflow into IAC steps, which are just plain desired and actual steps. The entire algorithm is driven by the RPM error term generated from the current and desired RPM. The desired RPMs are what the computer uses to alter the idle. I was under the impression the whole time that the above was pretty much lifted from the 8D and similar ecms and plunked in the TBI pcms. Evidently from the looks of it this is not the case, and I was making some ASSumptions instead.
Since I know nadda about how the 8D stuff works, is it possible to get a description of the idle routine in a nutshell, RBob? Seems like it would probably help Z69's understanding as well, and Im just sort of curious.
First time Ive ever looked at the 8D before and I got the wrong impression. My mistake.
Thats sort of a wacky way to do it. From what Ive seen so far, in the later PCMs the entire routine is based on airflow to make the proportional, integral, and derivative terms' action linear and at the end a lookup is done to translate the airflow into IAC steps, which are just plain desired and actual steps. The entire algorithm is driven by the RPM error term generated from the current and desired RPM. The desired RPMs are what the computer uses to alter the idle. I was under the impression the whole time that the above was pretty much lifted from the 8D and similar ecms and plunked in the TBI pcms. Evidently from the looks of it this is not the case, and I was making some ASSumptions instead.
Since I know nadda about how the 8D stuff works, is it possible to get a description of the idle routine in a nutshell, RBob? Seems like it would probably help Z69's understanding as well, and Im just sort of curious.
12-25-2005, 01:12 PM
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This is from the aujp code hac from the same section as listed in axcn above from LE72E: to LE76C: may need to line them up side by side to see what's going on or not going on....
I still need to update the comments once I'm sure what's going on- In this one of several pages of IAC code. IAC txt file
Added for clarity
The jmp to LE7C4 is a jmp to LE7DC in AXCN.
LE7C4 in aujp is part of the inject.src and skips all the listed IAC code.
I still need to update the comments once I'm sure what's going on- In this one of several pages of IAC code. IAC txt file
Added for clarity
Code:
LE6B9: ldaa L0111 ; REQUESTED IAC MOTOR STEPS ; CRef: 0xE6AF
bpl LE6CA ; BR IF STEPS ARE REQUESTED (Goes to LE6C2 IN ANHT)
; (TRAJECTORY DECAY)
; ... else
;
; TRAJECTORY DELAY
;
bitb #0x20 ; B5,PID CMD STEP ACTIVE
; (A/C STEPS BEING REMOVED ?)
bne LE6CA ; BR IF B5, IF SO, BYPASS DECAY (Goes to LE6C2 IN ANHT)
; ... else
dec L0114 ; DECREMENT IAC DECAY COUNTER VALUE
beq LE6CA ; IF DECAY DONE, STEP MOTOR (Goes to LE6C2 IN ANHT)
; ... else
jmp LE7C4 ; ELSE RETURN WITH NO STEP LE7C4 in aujp is part of the inject.src and skips all the listed IAC code.
Code:
LE736: ldab L0111 ; GET REQUESTED IAC MOTOR STEPS ; CRef: 0xE711,0xE71A,0xE71E
lslb ; DIV B by 2
beq LE769 ; BR IF EQUAL (Goes to LE761 IN ANHT)
; ... else
dec L0111 ; REQUESTED IAC MOTOR STEPS
ldab *L002B ; CURRENT IAC POSITION
bcc LE74B ; BR IF Carry Clear, NO OVERFLOW (Goes to LE743 IN ANHT)
; ... else
;---------------------
; EXTEND IAC PINTLE
; less air to engine
;---------------------
beq LE746 ; IF Z, SAVE CURRENT STATE (Goes to LE73E IN ANHT)
; ... else
decb ; ADJUST CURRENT POSITION DOWN
LE746: dec L011A ; DECREMENT IAC RUNNING COUNTER ; CRef: 0xE743
bra LE754 ; Branch to UP DATE A/C LEARN & THROTTLE FOLLOWER FLAGs
; (Is LE74C in ANHT)
;---------------------------------------------------------
;---------------------
; RETRACT IAC PINTLE
; more air to engine
;---------------------
LE74B: cmpb 0x42,x ; LIMIT POSIT TO MAX ; CRef: 0xE741
bcc LE769 ; BR IF LESS THAN MAXIMUM (Goes to LE761 IN ANHT)
; ... else
incb ; UP DATE IAC POSITION
inc L011A ; INCREMENT IAC RUNNING COUNTER
clc ; CLEAR THE "C" Carry Bit
;----------------------------------------------------------------------
; UP DATE A/C LEARN & THROTTLE FOLLOWER FLAGs (Is LE74C in ANHT)
;----------------------------------------------------------------------
LE754: stab *L002B ; CURRENT IAC POSITION Last edited by Z69; 12-25-2005 at 02:31 PM.
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