Question for tephra, others. RE: map header addition factors
Jun 14, 2008, 06:33 AM
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Question for tephra, others. RE: map header addition factors
This question was prompted by my own disassembly of an older ECU, and was partially answered in this thread:
http://www.aktivematrix.com/forum/vi...t=table+header
My question is in regard to the 2nd byte in the header. The addition value of 14. What does this mean? What effect does it have on the ECU's interpretation of the map? The definition files for ECUFlash just display the unaltered decimal equivalent of the raw hex values.
The reason I ask is this. I've got ROM dumps from various 3000GTs. The one I'm working on is from a 1995 (Mitsu 7793 CPU), and it has this for its high octane ignition header.
34 FC 0E FD 14 (little endian format)
FC34 - Address of X-axis
FD14 - Address of Y-axis
14 - Addition factor
The fuel maps use 00 for the last byte, consistent with the Evo. The MH7202F based 98 and 99 cars also use these addition factors, though the header format is slightly different.
A more detailed explanation would be very much appreciated
http://www.aktivematrix.com/forum/vi...t=table+header
Originally Posted by tephra
ok from the top
3 = 3d map, 2 would indicate 2d map
14 = addition value that gets applied to the values that are retrieved, ie for ignition timing maps its 0x14 (add 20), for fuel maps it will be 0
ffff877c = memory variable to use to lookup up 1 axis
ffff877e = memory variable to use to lookup up the other axis
13 = the number of elements in the X axis...
the axis definition contains the other axis element number...
3 = 3d map, 2 would indicate 2d map
14 = addition value that gets applied to the values that are retrieved, ie for ignition timing maps its 0x14 (add 20), for fuel maps it will be 0
ffff877c = memory variable to use to lookup up 1 axis
ffff877e = memory variable to use to lookup up the other axis
13 = the number of elements in the X axis...
the axis definition contains the other axis element number...
The reason I ask is this. I've got ROM dumps from various 3000GTs. The one I'm working on is from a 1995 (Mitsu 7793 CPU), and it has this for its high octane ignition header.
34 FC 0E FD 14 (little endian format)
FC34 - Address of X-axis
FD14 - Address of Y-axis
14 - Addition factor
The fuel maps use 00 for the last byte, consistent with the Evo. The MH7202F based 98 and 99 cars also use these addition factors, though the header format is slightly different.
A more detailed explanation would be very much appreciated
Jun 14, 2008, 06:53 PM
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Sorry about that. I just realized the typo probably ruined the whole thing.
Here's the first few bytes for all three of our timing maps (the whole map is 20x15).
0xF620 :34 FC 0E FD 14 <--------Map header
0xF625 :0F 0F 0F 14 1A 1D 1F 21 22 23 24 25 26 27 28 29 2A 2B 2C 2C <--------First row of timing map
0xF751 :34 FC 0E FD 14 <--------Map header
0xF756 :0F 0F 0F 14 1A 1D 1F 21 22 23 24 25 26 27 28 29 2A 2B 2C 2C <--------First row of timing map
0xF882 :34 FC 0E FD 14 <--------Map header
0xF887 :0F 0F 0F 14 1A 1D 1F 21 22 23 24 25 26 27 28 29 2A 2B 2C 2C <--------First row of timing map
So the header SHOULD read...
FC34 - Address of X-axis
FD0E - Address of Y-axis
14 - Addition factor
The fuel maps all read xx xx yy yy 00. No addition factor.
So all I'm trying to get at is this. On the Evo, if you've got a cell with value 0F (decimal 15) the ECU is actually using a baseline ignition advance of 29 degrees (prior to any other correction factors being added) ?
Here's the first few bytes for all three of our timing maps (the whole map is 20x15).
0xF620 :34 FC 0E FD 14 <--------Map header
0xF625 :0F 0F 0F 14 1A 1D 1F 21 22 23 24 25 26 27 28 29 2A 2B 2C 2C <--------First row of timing map
0xF751 :34 FC 0E FD 14 <--------Map header
0xF756 :0F 0F 0F 14 1A 1D 1F 21 22 23 24 25 26 27 28 29 2A 2B 2C 2C <--------First row of timing map
0xF882 :34 FC 0E FD 14 <--------Map header
0xF887 :0F 0F 0F 14 1A 1D 1F 21 22 23 24 25 26 27 28 29 2A 2B 2C 2C <--------First row of timing map
So the header SHOULD read...
FC34 - Address of X-axis
FD0E - Address of Y-axis
14 - Addition factor
The fuel maps all read xx xx yy yy 00. No addition factor.
So all I'm trying to get at is this. On the Evo, if you've got a cell with value 0F (decimal 15) the ECU is actually using a baseline ignition advance of 29 degrees (prior to any other correction factors being added) ?
Last edited by Gatecrasher R/T; Jun 14, 2008 at 06:59 PM.
Jun 14, 2008, 09:50 PM
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Cool. Thanks. I just wanted to be sure what I'm looking for. Sadly enough, our cars were out of production before yours were even officially introduced to this country...and we're still way behind the Evo crowd. I'm one of maybe 2 or 3 guys even bothering to work on this. 
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Jun 16, 2008, 01:37 AM
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No, its an adder.
You can see it in the ign Table. The 0x14 (20 dez) ist the adder for the ignition table values, to keep them in a positive range.
You can see it in the ign Table. The 0x14 (20 dez) ist the adder for the ignition table values, to keep them in a positive range.
Code:
ROM:00003B7A Ign_high_Table: .data.b 3 ; DATA XREF: ROM:Ign_high_Addr1o ROM:00003B7A ; ROM:00006138o ... ROM:00003B7B .data.b h'14 adder ROM:00003B7C .data.l RPM_Tab_Find ROM:00003B80 .data.l Load_Tab_Find ROM:00003B84 .data.b h'13 row/col size ROM:00003B85 .data.b 5 first Value pointed to in ecuflash ROM:00003B86 .data.b 5 ... ROM:00000C3A mov.b @(1,r1), r0 ; r9=r0= 2 tes Byte = 0 in fuel ROM:00000C3C extu.b r0, r9 ... ROM:00000C9C add r9, r4 ROM:00000C9E extu.b r4, r4 ROM:00000CA0 mov.b @(1,r8), r0 ; Wert danach ebenfalls ROM:00000CA2 add r9, r0 ROM:00000CA4 bsr sub_D7A ; Mittelwert der zweiten Spalte ROM:00000CA6 extu.b r0, r5
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