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Discussion Starter · #1 ·
Creating a thread to document learning about and implementing the AEM ECU to drive a dual-LDU vehicle.

The VCU300 and the Tesla LDU replacement logic boards are relatively new on the market and so not much in the way of support for newbies. The manual assumes a fair bit of basic knowledge and equipment is available on-hand so I'd like to fill in some of the blanks here as best I can in case it is helpful to others wishing to do similarly.

Please don't reply to this thread unless you have experience with this equipment or something relevant to add



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The ECU looks like a stock OEM Bosch unit, similar to a EDC17 CP44. The CPU plus the power and can bus pins match at least

The instructions don't detail the header particularly well, it is a Bosch 196P EMS which is available as a kit from AEM or separately elsewhere

These use two terminal types
Matrix 1.2 Series CB 1.5mm2
BTL2.8 1.5-2.5mm2

Bosch sell an expensive crimp tool, a generic open-barrel/Weatherpack crimper seems to work ok.

The smaller Matrix 1.2 terminals use a single depinning tool
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The larger BTL 2.8 pins require a dual fork depinning tool https://bosch-connectors.com/bcp/b2...ance/BTL-2-8-Disassembling-Tool/p/1928498715/
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The Tesla LDU replacement board is not yet officially supported for dual-motor installations, VCU300, or for the Sport LDU.
It appears to be the front-end of a Cascadia inverter, configured for the power stage of the LDU. Since the VCU300 supports dual Cascadia drives, it also supports dual LDUs, once I figure out how to change can addresses.

Micro is a TI TMS320F28374S which is about as good as it gets; they are used in aerospace applications. https://www.ti.com/lit/ds/symlink/tms320f28378s.pdf

RS232 programming link is interesting; a bit 1982 perhaps. Not sure how to update the firmware when it is installed in-situ if it is done via this header, that would require a full car disassembly as the inverter covers can't come off in place. Might need an extra cable making up. No instructions were included with the hardware.
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Any way you could sample continuity of a couple of pins between J10 and the TMS 320? The resistors at pins 2, 14, and 14 are smoking guns...

I suspect J10 is the JTAG factory programming connector (done with pogos):

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Which could lend itself to reprogramming the board if the processor's not locked out with fuse bits.
 

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Since the VCU300 supports dual Cascadia drives, it also supports dual LDUs, once I figure out how to change can addresses.
The base CAN address for the inverter control boards are set in the exact same way as they are set with Cascadia inverters. The default inverter address offset is 0x00A0. If a second unit is present then it's address offset should be set to 0x01A0.
 

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Discussion Starter · #4 · (Edited)
The base CAN address for the inverter control boards are set in the exact same way as they are set with Cascadia inverters
Thank you, I think I'm piecing it together. Is there an LDU board instruction manual to help me out?

Do I need to update the firmware, if so, which version? The AEM EVVCU Pre-Start Checklist Says I need to update but the date is several years old so presumably not necessary?
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So it turns out the RS232 port is on the encoder plug via an adapter loom. Not quite sure what the switch does yet, is this the "Flash Enable Jumper"?
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It communicates using RMS GUI 1.4.8 (aka Cascadia Motion GUI Setup) from Documentation - Electric Vehicle / Cascadia Motion which [edit] requires the installation of "GTK+2 Runtime Environment" first and a PC restart after install.

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Serial comms working, CAN ID changed, but no CAN comms to the VCU300 yet. Need to figure out the terminating resistor setting and do some sniffing tomorrow.

Assuming white is CAN+
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Discussion Starter · #5 ·
Error 9 (9 flashes of the on-board LED) shows until the can line is configured properly. After changing a few settings I got it to go off and the data now shows in Savvycan, however it is not yet replicated on the AEMCal screen.

Voltage and temp readings are sensible
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DBC file for the inverter is in "PM and RM series DBC files", this is separate from the DBC file for the VCU.
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Settings I had to change are the terminating resistor to off and fast message rate to 50ms. The inverter doesn't use extended frames
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Discussion Starter · #6 ·
Success, temps reading on AEMCal, once I figure out what I'm doing. The default layout screens don't have anything for the inverter feedback signals other than torque, rpm etc so it took a bit of digging to find them
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Next is to build a bench harness with accel sensor, brake switch and so on.

Also need to see if I can get the wheel speeds send from the Tesla Bosch (private) can network to the VCU. No instructions and no idea yet how to configure can signals from other sources. They are all 500kb speed at least.

Another activity I'd like the VCU to do is provide wake and assist signals for the power steering rack which is from a Subaru Impreza. It works if I inject the signals from Savvycan so just need to figure out how to get the VCU to generate and output the signals. If it has such a capability.
 
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