forked from espressif/esp-idf
feat(parlio_tx): support to mount bitscrambler
This commit is contained in:
Chen Jichang
morris
@ -129,6 +129,7 @@ The following are the configuration parameters of the :cpp:type:`parlio_transmit
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.. list::
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- :cpp:member:`parlio_transmit_config_t::idle_value` Sets the value on the data lines when the TX unit is idle after transmission. This value will remain even after calling :cpp:func:`parlio_tx_unit_disable` to disable the TX unit.
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:SOC_BITSCRAMBLER_SUPPORTED: - :cpp:member:`parlio_transmit_config_t::bitscrambler_program` The pointer to the bitscrambler program binary file. Set to ``NULL`` if the bitscrambler is not used in this transmission.
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- :cpp:member:`parlio_transmit_config_t::flags` Usually used to fine-tune some behaviors of the transmission, including the following options
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- :cpp:member:`parlio_transmit_config_t::flags::queue_nonblocking` Sets whether the function needs to wait when the transmission queue is full. If this value is set to ``true``, the function will immediately return the error code :c:macro:`ESP_ERR_INVALID_STATE` when the queue is full. Otherwise, the function will block the current thread until there is space in the transmission queue.
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:SOC_PARLIO_TX_SUPPORT_LOOP_TRANSMISSION: - :cpp:member:`parlio_transmit_config_t::flags::loop_transmission` Setting this to ``true`` enables infinite loop transmission. In this case, the transmission will not stop unless manually calling :cpp:func:`parlio_tx_unit_disable`, and no "trans_done" event will be generated. Since the loop is controlled by DMA, the TX unit can generate periodic sequences with minimal CPU intervention.
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@ -308,6 +309,17 @@ The waveform of the external clock input is shown below:
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If you need to modify the transmission payload after enabling infinite loop transmission, you can configure :cpp:member:`parlio_transmit_config_t::flags::loop_transmission` and call :cpp:func:`parlio_tx_unit_transmit` again with a new payload buffer. The driver will switch to the new buffer after the old buffer is completely transmitted. Therefore, users need to maintain two buffers to avoid data inconsistency caused by premature modification or recycling of the old buffer.
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.. only:: SOC_BITSCRAMBLER_SUPPORTED
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Custom Bitstream Generation with BitScrambler
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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We can use the :doc:`BitScrambler </api-reference/peripherals/bitscrambler>` assembly code to control the data on the DMA path, thereby implementing some simple encoding work. Compared to using the CPU for encoding, the BitScrambler has higher performance and does not consume CPU resources, but is limited by the limited instruction memory of the BitScrambler, so it cannot implement complex encoding work.
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After writing the BitScrambler program, we can enable it by calling :cpp:func:`parlio_tx_unit_decorate_bitscrambler`. And configure the :cpp:member:`parlio_transmit_config_t::bitscrambler_program` to point to the binary file of the BitScrambler program. Different transmission transactions can use different BitScrambler programs. The binary file must conform to the BitScrambler assembly language specification, and will be loaded into the BitScrambler's instruction memory at runtime. For details on how to write and compile the BitScrambler program, please refer to :doc:`BitScrambler Programming Guide </api-reference/peripherals/bitscrambler>`.
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:cpp:func:`parlio_tx_unit_decorate_bitscrambler` and :cpp:func:`parlio_tx_unit_undecorate_bitscrambler` need to be used in pairs. When deleting the TX unit, you need to call :cpp:func:`parlio_tx_unit_undecorate_bitscrambler` first to remove the BitScrambler.
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Power Management
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^^^^^^^^^^^^^^^^
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@ -129,6 +129,7 @@ TX 单元以比特为单位进行传输，且传输的比特长度必须配置
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.. list::
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- :cpp:member:`parlio_transmit_config_t::idle_value` 设置 TX 单元发送完毕后空闲状态时数据线上的值。该值在调用 :cpp:func:`parlio_tx_unit_disable` 禁用 TX 单元后依然会保持。
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:SOC_BITSCRAMBLER_SUPPORTED: - :cpp:member:`parlio_transmit_config_t::bitscrambler_program` 指向比特调节器程序的二进制文件的指针。若此次传输不使用比特调节器，则设置为 ``NULL``。
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- :cpp:member:`parlio_transmit_config_t::flags` 通常用来微调传输的一些行为，包括以下选项
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- :cpp:member:`parlio_transmit_config_t::flags::queue_nonblocking` 设置当传输队列满的时候该函数是否需要等待。如果该值设置为 ``true`` 那么当遇到队列满的时候，该函数会立即返回错误代码 :c:macro:`ESP_ERR_INVALID_STATE`。否则，函数会阻塞当前线程，直到传输队列有空档。
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:SOC_PARLIO_TX_SUPPORT_LOOP_TRANSMISSION: - :cpp:member:`parlio_transmit_config_t::flags::loop_transmission` 设置为 ``true``，会启用无限循环发送机制。此时，除非手动调用 :cpp:func:`parlio_tx_unit_disable`，否则发送不会停止，也不会生成“完成发送”事件。由于循环由 DMA 控制， TX 单元可以在几乎不需要 CPU 干预的情况下，生成周期性序列。
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@ -308,6 +309,17 @@ TX 单元可以选择各种不同的时钟源，其中外部时钟源较为特
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如果启用无限循环发送后需要修改发送内容，可以配置 :cpp:member:`parlio_transmit_config_t::flags::loop_transmission` 并再次调用 :cpp:func:`parlio_tx_unit_transmit` 传入新的 payload buffer，驱动会在旧 buffer 完整发送后，切换到新传入的 buffer。因此需要用户自行维护好两块buffer，避免旧 buffer 被提早修改或者回收导致产生数据不连贯的现象。
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.. only:: SOC_BITSCRAMBLER_SUPPORTED
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配合比特调节器 (BitScrambler) 产生自定义的比特流
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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我们可以通过编写 :doc:`比特调节器 </api-reference/peripherals/bitscrambler>` 汇编代码来控制 DMA 通路上的数据，进而实现一些简单的编码工作。相较于使用 CPU 做编码工作，比特调节器的性能更高，且不会占用 CPU 资源，但是受限于 BitScrambler 有限的指令存储器空间，它无法实现复杂的编码工作。
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编写好比特调节器程序后，通过调用 :cpp:func:`parlio_tx_unit_decorate_bitscrambler` 启用比特调节器。并在 :cpp:member:`parlio_transmit_config_t::bitscrambler_program` 配置本次传输使用比特调节器程序的二进制文件。不同的传输事务可以使用不同的比特调节器程序。该二进制文件必须符合比特调节器的汇编语言规范，并且在运行时会被加载到比特调节器的指令存储器中。如何编写并编译比特调节器程序请参考 :doc:`比特调节器编程指南 </api-reference/peripherals/bitscrambler>`。
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:cpp:func:`parlio_tx_unit_decorate_bitscrambler` 和 :cpp:func:`parlio_tx_unit_undecorate_bitscrambler` 需要成对使用。在删除 TX 单元时，需要先调用 :cpp:func:`parlio_tx_unit_undecorate_bitscrambler` 移除比特调节器。
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电源管理
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^^^^^^^^^^^^^^^^
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