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fix(rmt): calarify partial receive is not support on esp32

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because of lack hardware support
This commit is contained in:
morris
2024-04-01 14:22:53 +08:00
parent 71ceedc54f
commit d908150adc
5 changed files with 7 additions and 5 deletions
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docs/en/api-reference/peripherals/rmt.rst
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@@ -331,7 +331,7 @@ As also discussed in the :ref:`rmt-enable-and-disable-channel`, calling :cpp:fun
- :cpp:member:`rmt_receive_config_t::signal_range_min_ns` specifies the minimal valid pulse duration in either high or low logic levels. A pulse width that is smaller than this value is treated as a glitch, and ignored by the hardware.
- :cpp:member:`rmt_receive_config_t::signal_range_max_ns` specifies the maximum valid pulse duration in either high or low logic levels. A pulse width that is bigger than this value is treated as **Stop Signal**, and the receiver generates receive-complete event immediately.
- If the incoming packet is long, that they cannot be stored in the user buffer at once, you can enable the partial reception feature by setting :cpp:member:`rmt_receive_config_t::extra_flags::en_partial_rx` to ``true``. In this case, the driver invokes :cpp:member:`rmt_rx_event_callbacks_t::on_recv_done` callback multiple times during one transaction, when the user buffer is **almost full**. You can check the value of :cpp:member::`rmt_rx_done_event_data_t::is_last` to know if the transaction is about to finish.
- If the incoming packet is long, that they cannot be stored in the user buffer at once, you can enable the partial reception feature by setting :cpp:member:`rmt_receive_config_t::extra_flags::en_partial_rx` to ``true``. In this case, the driver invokes :cpp:member:`rmt_rx_event_callbacks_t::on_recv_done` callback multiple times during one transaction, when the user buffer is **almost full**. You can check the value of :cpp:member::`rmt_rx_done_event_data_t::is_last` to know if the transaction is about to finish. Please note this features is not supported on all ESP series chips because it relies on hardware abilities like "ping-pong receive" or "DMA receive".
The RMT receiver starts the RX machine after the user calls :cpp:func:`rmt_receive` with the provided configuration above. Note that, this configuration is transaction specific, which means, to start a new round of reception, the user needs to set the :cpp:type:`rmt_receive_config_t` again. The receiver saves the incoming signals into its internal memory block or DMA buffer, in the format of :cpp:type:`rmt_symbol_word_t`.