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I'm attempting to used the APM for an EV conversion and I'm looking for CAN BUS message definition for the APM. I'm using an Arduino with a CAN Bus shield to communicate with the APM. So far from what I've got in the net, the CAN Bus ID I've attempted to use is 0x1D4. What I've notice is that APM sends a message with ID 0x1D6.

Does GM publish the CAN BUS message definition or somebody have listing compiled from a sniffer? Thanks!
 

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Found the info in another forum. Sharing the can ID summary below in case someone is interested on it.

CAN ID 0x1D4 - to turn on and off the APM.
CAN ID 0x1D6 - displays voltage, temperature and apms.
CAN ID 0x495 - feedback info
 

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CAN Data:

The CAN data bus is at 500K and uses 11 bit ID’s.
In tests it seemed adequate to transmit the command at a rate of 100ms and the DC-DC didn’t seem to object to this.

Command ID 0x1D4 (2 byte message)
Byte 0
Bit 0 ?
Bit 1 ?
Bit 2 ?
Bit 3 ?
Bit 4 ?
Bit 5 DC-DC enable 1. A 1 is this bit enables the DC-DC, a 0 disables it.
Bit 6 ?
Bit 7 DC-DC enable 2. A 1 is this bit enables the DC-DC, a 0 disables it.

Byte 1 Output Voltage Command
The output voltage setpoint that the DC-DC is to regulate.
The scaling seems to be desired voltage * 12.7.
For example, to command 13.8V, you would send 13.8*12.7=175=0xAF

Feedback ID 0x1D6 (7 byte message)
Byte 0 ?

Byte 1 ?

Byte 2 LV Output Voltage
The DC voltage as measured on the output.
The value is obtained by dividing by 12.7. For example if the value is 0xAC then
The voltage would be 0xAC=172 / 12.7 =13.5VDC

Byte 3 Coolant or baseplate temperature 1
Temperature in degrees C with a -40C offset.
A value of 0x55 = 85 = 45 degrees Celsius (85-40).

Byte 4 Coolant or baseplate temperature 2
Temperature in degrees C with a -40C offset.
A value of 0x55 = 85 = 45 degrees Celsius (85-40).

Byte 5 LV output Current
The output current of the DC-DC converter.
The value is scaled 1:1, so a value of 0x55 = 85ADC

Byte 6 ?
 
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