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Transitioning Applications from CAN 2.0 to CAN FD
Wilhelm Leichtfried
Orlando Esparza Fernando Gonzalez
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Driver Door Module
Transitioning Applications from CAN 2.0 to CAN FD Wilhelm - - PowerPoint PPT Presentation
Transitioning Applications from CAN 2.0 to CAN FD Wilhelm - - PowerPoint PPT Presentation
Transitioning Applications from CAN 2.0 to CAN FD Wilhelm Leichtfried Orlando Esparza Fernando Gonzalez October 2015 Application Driver Door Module 2 Requirements CAN 2.0 DDM Analog: Temperature Sensor Inputs: door lock, window lift,
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Requirements CAN 2.0 DDM
Analog: Temperature Sensor Inputs: door lock, window lift, mirror control, door ajar Outputs: window and door lock driver Interior Lighting: LED intensity control Communication:
CAN 2.0: 500kb/s; 75% sample point +/-0.4% bit time tolerance LIN: 19.2kb/s; for mirror control
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Communication: CAN 2.0
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Temperature Sensor Door Lock Door Ajar Mirror Control Window Lift Control LIN Transceiver A2D Digital In UART CAN 2.0 CAN 2.0 Transceiver Door Lock Driver Window Motor LED Driver Digital Out
MCU
FLASH RAM CPU PLL PWM 48 MHz 8 MHz
CAN 2.0 HW
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CAN 2.0 FW
Communication Drivers UART Driver CAN Driver I/O Drivers I/O Driver MCU Peripherals CAN UART I/O
- Comm. Hardware Abstraction
I/O Abstraction CAN Interface LIN Interface Application I/O Interface CAN Network Management LIN Network Management Door Un/Lock Window Lift
- Temp. Sensing
Interior Lighting CAN 2.0 Transceiver LIN Transceiver
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Development Effort
Hardware design: 1 TQ Firmware design: 3-5 TQ Validation: 3-5 TQ
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Motivation for CAN FD
OEM face bandwidth issues
EOL programming Growth of features
Limits of CAN 2.0
500kb/s data rate 8 data bytes per message
Solution -> CAN FD
500kb/s arbitration phase; 2Mb/s data phase 5 to 8Mb/s programming 64 data bytes per message
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CAN 2.0 vs. CAN FD
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Requirements CAN FD DDM
Temperature – send data more often Inputs: door lock, window lift, mirror control, door ajar Outputs: window and door lock driver Interior Lighting: RGB LED Communication:
CAN FD: 500kb/s-2Mb/s; 75.0% sample point; +/-0.4% bit time tolerance; 40 (or 20 or 80) MHz CAN clock LIN: for mirror control
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Temperature Sensor Door Lock Door Ajar Mirror Control Window Lift Control LIN Transceiver A2D Digital In UART CAN 2.0 CAN 2.0 Transceiver Door Lock Driver Window Motor LED Driver Digital Out
MCU
FLASH RAM CPU PLL PWM 48 MHz 8 MHz
CAN FD HW
FLASH RAM CAN FD Transceiver CAN FD RGB LED Driver 4x PWM 64 MHz 40 MHz
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CAN FD FW
Communication Drivers UART Driver I/O Drivers I/O Driver MCU Peripherals CAN FD UART I/O
- Comm. Hardware Abstraction
I/O Abstraction LIN Interface Application I/O Interface LIN Network Management Door Un/Lock Window Lift
- Temp. Sensing
CAN FD Transceiver LIN Transceiver CAN Driver CAN Interface CAN Network Management Interior Lighting RGB Interior Lighting CAN FD Driver CAN FD Interf. CAN FD Network M.
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CAN FD MCU availability
Limited number of CAN FD MCU Most MCUs are high end targeting Gateway applications Major re-design effort of HW and FW Major re-validation effort
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New MCU FW
Communication Drivers UART Driver I/O Drivers I/O Driver MCU Peripherals CAN FD UART I/O
- Comm. Hardware Abstraction
I/O Abstraction LIN Interface Application I/O Interface LIN Network Management Door Un/Lock Window Lift
- Temp. Sensing
CAN FD Transceiver LIN Transceiver CAN Driver CAN Interface CAN Network Management Interior Lighting RGB Interior Lighting CAN FD Driver CAN FD Interf. CAN FD Network M. UART Driver I/O Driver LIN Interface I/O Interface
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Temperature Sensor Door Lock Door Ajar Mirror Control Window Lift Control LIN Transceiver A2D Digital In UART Door Lock Driver Window Motor LED Driver Digital Out
MCU
FLASH RAM CPU PLL PWM FLASH RAM CAN Transceiver CAN 2.0 RGB LED Driver 4x PWM 64 MHz CAN FD Transceiver CAN FD Controller SPI 4 MHz
External Controller
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External CAN FD Controller FW
Communication Drivers UART Driver I/O Drivers I/O Driver MCU Peripherals SPI UART I/O
- Comm. Hardware Abstraction
I/O Abstraction CAN FD Interf. LIN Interface Application I/O Interface CAN FD Network M. LIN Network Management Door Un/Lock Window Lift
- Temp. Sensing
RGB Interior Lighting CAN FD Controller/XCVR LIN Transceiver CAN Driver SPI Driver
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External Controller
Benefit of Using an External Controller
Maximize design re-use Minimize cost
Keep microcontroller No need to upgrade to available high end CAN FD MCU Minimize re-validation
Increased choices of MCU Easily add additional CAN FD channels
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External CAN FD controller blockdiagram
SPI Interface CAN Clock Generation SPI Pins INT Pins RAM TX/RX Msg Objects TX/RX FIFOs
TXCAN RXCAN
BSP Bit Stream Processor TX Handler TX Prioritization RX Handler Acceptance Filter Memory IF CAN SFR Mode Control Time Stamping CAN Interrupts FIFO and Buffer Control Filter and Masks
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External CAN FD controller FAQ
Are there security considerations?
Add ECC to RAM Secure SPI with optional CRC
What is the required SPI speed?
500k/2M -> 10MHz 500k/5M -> 12MHz SPI with DMA recommended
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CAN FD bit time setup
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Summary
CAN 2.0 to CAN FD transition has begun
Both Automotive and Industrial
Lack of CAN FD capable MCUs
Increases OEM/Supplier costs and complexities
CAN FD External Controller is a viable alternative solution
Maximizes hardware and firmware reuse
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