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Post Info TOPIC: 76C55 (MH6311) information
Bob


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76C55 (MH6311) information
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I’ve attached a picture of the pins that I have traced out .

The picture I used is correct in it’s numbering and orientation but the labels are not correct so you will see that I’m re-labelling  as I test the pins.

The enable flash read pin is of interest as it is not connected on one of the factory ecus that I have (components not fitted to board), it is however connected on the Ralliart ecu which would have been mapped by them instead of Mitsubishi direct.

That particular pin allows the h8 chip and the sh chip be read on later ecus.

if needed I’ll trace out the output sides of this chip.

Theres is a couple of sensors like maf/cam/crank etc feed into a secondary chip labeled e310a which I’m guessing is like and analog to digital converter.

which pin is port 1 ?



-- Edited by Bob on Monday 30th of March 2020 04:22:06 PM

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Bob wrote:
Is there anything I can be doing to help?

 


 If you could trace out a couple of the analogue inputs and find out what pins they are connected to that would be useful, I don't have a pinout for the TCU that I have.

 

I have made a little more progress, I have located the pins for PORT1, tomorrow I will try and find PORT2. My emulator is not working correctly so progress is slow because I have to erase and burn an EPROM each time I need to modify the code.



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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.

Bob


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Yes it is ma7815

ive attached 2 pictures.



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Bob wrote:
What kind of code do you run on an unknown chip? 

Its not entirely unknown, its from the same family as the smaller chips and it was determined years back that they used a superset of the 6301 instruction set. I have compared the code with that from an earlier processor and can I see some similarities (and differences) in the architecture. At the moment the plan is to copy the existing configuration settings and then toggle each of the outputs in turn and see what pin changes. I'm also trying to send data out of the serial port.

 

The hybrid on your board, is that also a 7815?



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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.

Bob


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Thats good news that progress has been made.
What kind of code do you run on an unknown chip? 
I had a look over the EA528A circuit you posted and that is above my level of understanding at the moment as I’ve never encountered a need to understand a chip like that, but I’m guessing by understanding how that circuit works will allow you to get around it.
Is there anything I can be doing to help?

TechSupport wrote:

I've been able to run some code on the board but, as I suspected, the watchdog timer is causing issues. The watchdog timer is part of a hybrid circuit MA7815which looks to be very similar in operation to the EA528A fitted to many Suzuki ECUs. I've just published the timing diagram for that on this thread: https://rhinopower.activeboard.com/t30468381/33920-70e10-vitara-16-8v-tbi-1999/

I will instrument the TCU tomorrow and try to sniff out the port pin that resets the watchdog.


 



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I've been able to run some code on the board but, as I suspected, the watchdog timer is causing issues. The watchdog timer is part of a hybrid circuit MA7815which looks to be very similar in operation to the EA528A fitted to many Suzuki ECUs. I've just published the timing diagram for that on this thread: 

https://rhinopower.activeboard.com/t30468381/33920-70e10-vitara-16-8v-tbi-1999/

I will instrument the TCU tomorrow and try to sniff out the port pin that resets the watchdog.



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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.

Bob


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yeah hopefully it is possible to pull the on board rom as I’m looking forward to having a look at the maps on board my 24 year old Ralliart ecu.



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The RAM is internal, EPROM is external. This particular ECU has a 27C512 EPROM so the complete 64k address space can be utilised, once we get inside the chip we will see how much ROM it has.



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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.

Bob


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So is the 12k rom and the 1463 bytes of ram what the mh6311 has on board ,or what it has access to on the eprom?

 



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I located the EPROM chip and I've performed a crude disassembly. First impressions are that it has a, relatively, huge interrupt vector table - 46 entries. I think I've located the serial port interrupt vector and code so I have  a port that I can use to stream out the internal ROM. The processor has an 'E' number so it will have some code in it. First I will load the stock configuration and then some code to send a square wave to each of the outputs in turn to sniff out the port pins.



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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.



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The safety chip performs similar functions, on the older engine ECUs it can often generate the limp signals to drive the injectors and ignition. I may need to cut a track or lift a component, I should be able to find the reset line in the code and just toggle it to keep the ECU 'alive'

I found the original EPROM, the code uses 12k of EPROM and 1463 bytes of RAM, the E clock runs at 4MHz. By comparison the 76C175/MH6211 has 4k of ROM, 447 bytes of RAM and runs at 2MHz.



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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.

Bob


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Very interesting 

out of interest does that safety chip on that gearbox control unit perform the same function as the “limp home” chip in an engine ecu as you have described in one of the articles on tuning the stock ecus?

when you disable the watchdog are you simply cutting a trace or removing a chip?

That 80 pin chip on the bottom of the board would interest me at a later date as I believe it to be the same used on later ecus to process maf/crank/cam etc signals before be sent to the main h8 or sh processor .

 



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I don't have any 74HC165 chips on my ECU, I would think that is some sort of peripheral interface so the data lines would go to it and there would be an address decoder for it. What I am working with is this:

 

DSM TCU MH6311 76C55

 

The small square chip with the blue resonator is the 'safety' chip, I will need to disable the watchdog; the bottom chip is a port expander with some address decoding; the empty slot is for the EPROM. I'm sorting out the missing firmware at the moment, when I get that I will copy the configuration from it and then run some custom code on the ECU - hopefully it has a serial port I can utilise.



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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.

Bob


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Are the data lines the ones going to the dual shift register 74hc165 chips ?
I had a quick look at the data sheet page and did not see the updated pinouts but I may have missed them .

Im excited to see weather or not this chip can be read.

 

TechSupport wrote:

I've no data at all for the MD759132 and no EPROM. I've traced out the data and address lines and I was able to figure out the 12V power pins and run it up. I've updated the datasheet page and if I find some time tomorrow I will write some code for it and see what happens. If it uses the same die as the 84-pin chips then the pinout should be similar, relatively.


 



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Bob


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Firstly I’d like so say thanks for taking an interest in this and for helping out.
To answer you’re question,yes I have access to a friends evo 3 ecu with external eprom that is using ostrich 2.0 .
Also in regards to the fto transmission ecu I can get one of them too but that will be next weekend.
I also have an arduino that I can set up to do a serial read and probably get it to pull the mode pins to 0v for what ever time is required.
As for powering up my ecu I have it on a bench at the moment and have various sensors hooked up and can read the values through the obd2 port and a program call evoscan.

 

TechSupport wrote:

The memory size is 4k on the 84-pin chips so it sits at C000h in the memory map, you may have more or less memory. To read the memory you need to load a program into an external memory device that will then be run in Mode 0 and will read the internal memory out through the serial port so you need to find that as well, you may have some test points on those traces. I use a 27C256 as the external memory and place the ROM reader programme lower down on the memory map to avoid bus contentions with internal memory.

I tend to just dump the entire memory map, it will copy the RAM and the reader programme but that can be edited out. The code usually starts at the bottom of the memory so that's easy to find. The Stack Pointer is set to the end of RAM, that location will be found in the first few bytes of RAM. You only have a 16-bit address bus so the memory range is 64k max.

Do you have access to an ECU with an external EPROM? if not then you won't easily be able to determine the pins for the data and address lines, it is possible but its extra work.

I originally had a Suzuki Vitara with a 70E10 ECU, this had an 84-pin chip with an external EPROM; that was the first of these processors that I reversed engineered. The mode pins will be near the crystal somewhere, I did have an ECU with the 100-pin chip years ago but I've no idea what happened to it. I'll have a look for it - it may just have been an odd one that came in for repair.

 

Edit: I found the ECU very quickly, its an MD759132 which Google says is a Mitsubishi FTO Gearbox ECU, the one I have has no EPROM fitted, I'll have a look for that too.



-- Edited by TechSupport on Sunday 15th of March 2020 12:02:01 PM


 



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I've no data at all for the MD759132 and no EPROM. I've traced out the data and address lines and I was able to figure out the 12V power pins and run it up. I've updated the datasheet page and if I find some time tomorrow I will write some code for it and see what happens. If it uses the same die as the 84-pin chips then the pinout should be similar, relatively.



__________________

1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.



Guru

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Posts: 1228
Date:
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The memory size is 4k on the 84-pin chips so it sits at C000h in the memory map, you may have more or less memory. To read the memory you need to load a program into an external memory device that will then be run in Mode 0 and will read the internal memory out through the serial port so you need to find that as well, you may have some test points on those traces. I use a 27C256 as the external memory and place the ROM reader programme lower down on the memory map to avoid bus contentions with internal memory.

I tend to just dump the entire memory map, it will copy the RAM and the reader programme but that can be edited out. The code usually starts at the bottom of the memory so that's easy to find. The Stack Pointer is set to the end of RAM, that location will be found in the first few bytes of RAM. You only have a 16-bit address bus so the memory range is 64k max.

Do you have access to an ECU with an external EPROM? if not then you won't easily be able to determine the pins for the data and address lines, it is possible but its extra work.

I originally had a Suzuki Vitara with a 70E10 ECU, this had an 84-pin chip with an external EPROM; that was the first of these processors that I reversed engineered. The mode pins will be near the crystal somewhere, I did have an ECU with the 100-pin chip years ago but I've no idea what happened to it. I'll have a look for it - it may just have been an odd one that came in for repair.

 

Edit: I found the ECU very quickly, its an MD759132 which Google says is a Mitsubishi FTO Gearbox ECU, the one I have has no EPROM fitted, I'll have a look for that too.



-- Edited by TechSupport on Sunday 15th of March 2020 12:02:01 PM



__________________

1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.



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Continuing from here: https://rhinopower.activeboard.com/forum.spark?aBID=133095&topicID=30481695&p=3

 



__________________

1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine
2000 Suzuki Vitara 1.6 8V, many mods
2004 Suzuki Ignis 1.5VVT 4Grip
2006 Suzuki Jimny 1.3VVT JLX+
and many more.

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