It's remarkable that after nearly 20 years the Toyota Computer Control System (TCCS) engine management computer used for the 7M remains a mystery as far as the public domain is concerned. Partly, this is because it uses a proprietary Denso microprocessor with zero official documentation available outside of Toyota, and also because the 12kB of ROM code is burned into the microprocessor itself making extraction a major effort, and also preventing any code changes without adding a complex daughter board to allow the processor to run with external memory.
Although several commercial companies cracked it (Techtom, Mines) they kept everything secret and in the case of Techtom even went as far as to encrypt their own code to discourage reverse engineering.
One Japanese site run by H. Kashima has published significant information on the microprocessor architecture, including schematic and layout of a nice board to read the code burned into the microprocessor. He also developed a disassembler for the processor, and has put together a datasheet for the chip pinout, register and memory structure, and so on. Probably because it is written in Japanese, and also because Kashi decided to sell his disassembler and processor datasheet rather than make them public domain, not too many have taken advantage of his hard work in this area.
Recently, Jeremy Ross a guy who hangs out on the UK MR2 forum IMOCUK, has developed a very nice daughter board and software to allow real time data logging and updating of the code tables in the MR2 Gen 1 and 2 ECUs, which are essentially identical to the 7M ECUs of the same vintage. However, Jeremy keeps most of his info to himself, and obviously has plans to sell his ECU kits, so once again nothing gets disclosed publicly.
Against this backdrop of secrecy, there is one glimmer of hope, which is a Canadian based Toyota ECU Wiki. Although not exactly a hotbed of activity, it does have some of Kashi’s stuff translated to English, and also a public domain disassembler for the micro written in Perl.
So, the purpose of this thread will be to read out and analyze the code embedded in these ECUs, and to analyze and publish the various fuel/ignition maps and algorithms used by the 7M ECU.
Acknowledgements:
A couple of people on the forums have helped me out by donating ECUs, and or getting them to me at way below market value.
S383mmber1 (William) gave me a 7MGE M/T ECU. This is an early ECU with only a single circuit board inside. As such, it is probably the best place to start as it is the simplest to analyze.
Supraholics (Miguel) sent me two ECUs including a grey plug 7MGTE M/T ECU for shipping only. This is going to be my first mule for testing things out.
Although several commercial companies cracked it (Techtom, Mines) they kept everything secret and in the case of Techtom even went as far as to encrypt their own code to discourage reverse engineering.
One Japanese site run by H. Kashima has published significant information on the microprocessor architecture, including schematic and layout of a nice board to read the code burned into the microprocessor. He also developed a disassembler for the processor, and has put together a datasheet for the chip pinout, register and memory structure, and so on. Probably because it is written in Japanese, and also because Kashi decided to sell his disassembler and processor datasheet rather than make them public domain, not too many have taken advantage of his hard work in this area.
Recently, Jeremy Ross a guy who hangs out on the UK MR2 forum IMOCUK, has developed a very nice daughter board and software to allow real time data logging and updating of the code tables in the MR2 Gen 1 and 2 ECUs, which are essentially identical to the 7M ECUs of the same vintage. However, Jeremy keeps most of his info to himself, and obviously has plans to sell his ECU kits, so once again nothing gets disclosed publicly.
Against this backdrop of secrecy, there is one glimmer of hope, which is a Canadian based Toyota ECU Wiki. Although not exactly a hotbed of activity, it does have some of Kashi’s stuff translated to English, and also a public domain disassembler for the micro written in Perl.
So, the purpose of this thread will be to read out and analyze the code embedded in these ECUs, and to analyze and publish the various fuel/ignition maps and algorithms used by the 7M ECU.
Acknowledgements:
A couple of people on the forums have helped me out by donating ECUs, and or getting them to me at way below market value.
S383mmber1 (William) gave me a 7MGE M/T ECU. This is an early ECU with only a single circuit board inside. As such, it is probably the best place to start as it is the simplest to analyze.
Supraholics (Miguel) sent me two ECUs including a grey plug 7MGTE M/T ECU for shipping only. This is going to be my first mule for testing things out.
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