d398a6ced2
- CitrineOS core extracted (CSMS OCPP 2.0.1) - OpenOCPP extracted (firmware OCPP 1.6J/2.0.1) - ShapeShifter library installed (pip install -e) - ShapeShifter specification extracted - EVerest extracted TODO updated with progress
67 lines
2.2 KiB
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67 lines
2.2 KiB
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.. _everest_modules_handwritten_TIDA010939:
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.. **********
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.. TIDA010939
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.. **********
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The module ``TIDA010939`` is a board support driver for Texas Instruments
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TIDA-010939 reference design. It is based on the Yeti driver with similar structure
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and functionality.
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Communication between the TIDA010939 microcontroller and this driver module
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============================================================================
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The hardware connection between TIDA010939 and the host system (the board running EVerest and
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this module) is 3.3V TTL UART plus 2 GPIOs (one to reset the microcontroller
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from Linux and one to boot into the bootloader).
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The default configuration is 115200 bps 8N1.
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Protocol
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========
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EVerest can send commands to TIDA010939 and TIDA010939 publishes data and events back
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to EVerest. The packets are defined with protobuf to serialize the C structs
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into a binary representation that is transferred over the serial wire in a
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stream:
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https://developers.google.com/protocol-buffers
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To be able to split the stream back into packets all data is encoded using COBS
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before it is transmitted on the UART:
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https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing
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COBS
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----
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COBS is implemented in ``tida_010939_comms/evSerial.cpp``. Whenever a new packet
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was extracted from the stream ``handlePacket()`` is called to decode protobuf
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and generate the corresponding signals.
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Other parts of the module subscribe to these signals to handle the incoming
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packets.
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For TX ``linkWrite`` encodes the packet with COBS and outputs it to the UART.
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Protobuf
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--------
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The actual packet definitions are located under ``tida_010939_comms/protobuf``.
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``tida_010939.proto`` contains all messages that can be sent from EVerest to TIDA010939 and
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all messages that TIDA010939 sends to EVerest.
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Refer to these files for an up to date definition as they may change
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frequently.
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To generate the C code nanopb is used:
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``nanopb_generator -I . -D . *.proto``
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The output should also be manually copied to TIDA010939 Firmware to ensure the same
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definition is used on both sides when making changes.
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References
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============
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`Official website https://www.ti.com/tool/TIDA-010939 <https://www.ti.com/tool/TIDA-010939>`_
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