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The Oki 6260A was manufactured for Honda by Oki.

J. Wong has this to say: "I was just cleaning out my cube and just happened to run across a piece of paper with 6260A info on it... according to OKI UK Ltd, the official name for the chip is "Engine Control Counter IC" and it was discontinued in the mid '90's"

As of 10/10/03, we do not have any documentation on it. Most of the OBD0 developers would pay $$$ for documentation on it. What we know is 100% reverse engineering :)

The chip appears to be VERY multi-purpose.

Known functions:

  • Switching injectors on/off(pre-driving - TTL level)
  • Switching ignition out signal on/off(pre-driving - TTL level)
  • Switching outputs(purge, auto trans, CEL, etc.) on/off

Postulated Functions:

  • Monitoring on/off inputs(???)
  • Monitoring Distributor signals and generating timing interrupts.

;: MOVX A,@DPTR / MOVX @DPTR,A : where 2000 <= DPTR < 3000 (or is it 4000?) will talk to the 6260A.

Writing data to the 6260A @ 2000h is known to control IO lines on the chip. Johnathan Wong says: my theory is that if the high bit is off, it turns a digital output line on and if it the high bit is on, it turns it off ... the lower 7 bits are an "address".

The following table illustrates which values written @2000h control which pins on the chip(blank indicates use within the ROM but unknown function):

High Data Low Data Pin Function
90 10    
91 11    
92 12 24 Function unknown
93 13 22 Igniter trigger output
94 14 32 Main relay driver
95 15 33 AC relay driver
96 16 45 Q35 - Error LED on ECU
97 17 44 Q33 p3
a0 20 43 Fast idle solenoid
a1 21 42 Q31, Q45, CN1 Pin 11
a2 22 41 CEL on dash
a3 23 40 IC17-Auto Trans Lock Up
a4 24 39 Multipurpose output
a5 25 15 TDC Sensor Input ????
a7 27    

Thanks to Johnathan Wong, Javier and Mark Lamond for their help putting this table together. Are you curious how the 6260 ATesting was performed?

This table illustrates which input could be read at which address:

Address Pin Function
2001.1 60 A/C Switch
2001.3 59 ignition switch
2001.4 58 heater fan switch (hf)
2001.5 57 reverse switch (hf)
2001.6 56 clutch switch (hf) / traces to fuse box ('88-91 JDM Si R?)
2001.7 55 brake switch
2002.0 54  
2002.1 53  
2002.2 52  
2002.3 51  
2002.4 50  
2002.5 49  
2002.6 48  
2002.7 47  

2004 64 RPM low byte
2005 64 RPM high byte
2006 61 VSS low byte
2007 61 VSS high byte

Reading of address 2000h seems to deliver status information about the counters (like RPM, VSS, CYP/CID). Writing to address 2000h with bit 4 = bit 5 = 0 seems to control behaviour of either the counters or the pulse width modulators (PWM). 200F looks like a general control register.

Author: lestard Date: 05-23-03 07:03

these are the very first bytes the ecu exchanges with 6260:

6260bit Addr. hex address Data Value R/W Function
0000 0000 (2000h) 0000 0000 (00h) W  
0000 0000 (2000h) 0010 0101 (25h) W TDC sensor?
0000 0000 (2000h) 1001 0110 (96h) W error LED on ECU - off?
0000 0000 (2000h) 1010 0111 (A7h) W  
0000 1111 (200Fh) 1110 1001 (E9h) W  
0000 0011 (2003h) 1000 0000 (80h) R  
0000 0000 (2000h) 1010 0000 (A0) W fast idle solenoid off?
0000 0011 (2003h) 1000 0000 (80h) R  
0000 0001 (2001h) 0000 0000 (00h) W  
0000 0011 (2003h) 0000 0001 (01h) W  
0000 0011 (2003h) 1000 0001 (81h) R  
0000 0010 (2002h) 0000 0001 (01h) W  
0000 0011 (2003h) 1000 0000 (80h) R  

The connections of the 6260A have been mapped out fairly well. Thanks a bunch George and Mark Lamond!

Function Connection Pin M6260A Pin Connection Function
GND GND 1 M6260A 64   RPM Sensor Input
A0? MCU P0.0 2 M6260A 63 BACK pin33  
A1? MCU P0.1 3 M6260A 62   CID Sensor Input
A2? MCU P0.2 4 M6260A 61   VSS Sensor Input
A3? MCU P0.3 5 M6260A 60   A/C Switch Input
A4? MCU P0.4 6 M6260A 59 2904pin7  
A5? MCU P0.5 7 M6260A 58 RM4pin6  
A6? MCU P0.6 8 M6260A 57 RM4pin4  
A7? MCU P0.7 9 M6260A 56 RM4pin3  
!CE? MCU P2.4 10 M6260A 55 RM7pin2  
A8?? MCU P2.5 11 M6260A 54 Q18 Injector 1 pre-driver
LE? MCU ALE 12 M6260A 53 Q19 Injector 2 pre-driver
!WE? MCU !WR 13 M6260A 52 Q20 Injector 3 pre-driver
!OE? MCU !RD 14 M6260A 51 Q21 Injector 4 pre-driver
TDC Sensor Input   15 M6260A 50 RM7pin7 – Q16pin2 Feedback on auto trans
  IC14 pin7 16 M6260A 49 RM7pin8 - Q17pin2 Feedback on purge solenoid
  BA226A … R85 17 M6260A 48 BR6 Pulled high/low
  C61 18 M6260A 47 BR5 Pulled high/low
  BACK pin14 19 M6260A 46   VCC
  UPD7004 C pin3 20 M6260A 45 Q35 Error LED on ECU
  R48 21 M6260A 44 Q33 p3  
Igniter trigger output   22 M6260A 43   Fast idle solenoid
Multipurpose output   23 M6260A 42 Q31, Q45 CN1 Pin 11
  HC04 pin3 HC123 pin10 to R42 (pull) 24 M6260A 41   CEL on dash
+5V +5V 25 M6260A 40 IC17 Auto Trans Lock Up
+5V +5V 26 M6260A 39   Multipurpose output
GND GND 27 M6260A 38 Q24 Injector 1 “input”
FB2 7004C pin 17 28 M6260A 37 Q25 Injector 2 “input”
FB1 MCU pin19 (XTAL – clock) 29 M6260A 36 Q26 Injector 3 “input”
  R47 – 6260pin31 30 M6260A 35 Q27 Injector 4 “input”
  R47 – 6260pin30,C59,C60 31 M6260A 34   Main relay driver
GND GND 32 M6260A 33   A/C clutch relay

;:Table reflects 6260A-MJL-14Jul03.doc.

Revision: r1.5 - 02 Mar 2005 - 13:31 GMT - l3st4rd { Edit | Attach | History | More }
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