Framing

• Trice messages are framed binary data, if framing is not disabled.
• Framing is important for data disruption cases and is done with TCOBS (has included data compression) but the user can force to use COBS, what makes it easier to write an own decoder in some cases or disable framing at all.
  • Set TRICE_DIRECT_OUT_FRAMING and/or TRICE_DEFERRED_OUT_FRAMING inside triceConfig.h and use the Trice tool -packageFraming switch accordingly.
• For robustness each Trice can get its own (T)COBS package (TRICE_DEFERRED_TRANSFER_MODE == TRICE_SINGLE_PACK_MODE). That is configurable for transfer data reduction. Use #define TRICE_DEFERRED_TRANSFER_MODE TRICE_MULTI_PACK_MODE inside triceConfig.h (is now default). This allows to reduce the data size a bit by avoiding many 0-delimiter bytes but results in some more data loss in case of data disruptions.

Encoder dependencies follow the active outputs. Select direct framing with TRICE_DIRECT_OUT_FRAMING and deferred framing with TRICE_DEFERRED_OUT_FRAMING. An inactive output’s framing setting adds no dependency. For example, a direct-only COBS application does not need TCOBS despite the deferred framing default.

Active output framing	Required encoder source	Encoder sources that can be omitted
TCOBS only	src/tcobsv1Encode.c	src/cobsEncode.c
COBS only	src/cobsEncode.c	src/tcobsv1Encode.c
NONE only	None	Both encoder sources
Direct COBS and deferred TCOBS, or the reverse	Both encoder sources	Neither

These selective builds work without LTO, optimization or linker removal of unused sections. Encryption-disabled builds need no src/xtea.c; builds without RTT need no src/SEGGER_RTT.c or project RTT configuration. With the Trice backend disabled (TRICE_OFF or TRICE_CLEAN, without counted typeX0 transmission), retained UART settings do not require triceUart.h or UART hardware hooks. The minimal demos still compile src/*.c for simplicity; removing unreferenced code from such a complete-library build remains a separate image-size optimization.

TriceEncode(encrypt, framing, dst, buf, len) keeps its runtime framing argument. By default, TRICE_COBS_ENCODE_SUPPORT and TRICE_TCOBS_ENCODE_SUPPORT include exactly the encoders needed by active outputs. If your own code calls this API with additional framing methods, enable the corresponding support in triceConfig.h and link its encoder source. For example, add runtime COBS to an otherwise TCOBS-only application with:

#define TRICE_COBS_ENCODE_SUPPORT 1

Use TRICE_TCOBS_ENCODE_SUPPORT 1 to add runtime TCOBS instead. Both switches accept only 0 or 1; disabling an encoder required by an active output is a compile-time error. A request for a framing method not included in the build returns 0, leaves the source and destination untouched, and produces no fallback frame. Unknown framing values also return 0. NONE remains available without either encoder; its return value is the copied byte count, without a delimiter. Check the return value before sending the destination buffer.

The encoder dependency tests link isolated native projects at -O0, decode their real output, and check disabled outputs and runtime opt-ins. They also inspect ARM GCC objects when that toolchain is installed; no test relies on LTO or unused-section removal.

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