diff --git a/components/esp_driver_rmt/src/rmt_tx.c b/components/esp_driver_rmt/src/rmt_tx.c index e6006fa788..6e8649d2c6 100644 --- a/components/esp_driver_rmt/src/rmt_tx.c +++ b/components/esp_driver_rmt/src/rmt_tx.c @@ -648,20 +648,22 @@ size_t rmt_encode_check_result(rmt_tx_channel_t *tx_chan, rmt_tx_trans_desc_t *t rmt_encode_state_t encode_state = RMT_ENCODING_RESET; rmt_encoder_handle_t encoder = t->encoder; size_t encoded_symbols = encoder->encode(encoder, &tx_chan->base, t->payload, t->payload_bytes, &encode_state); + bool is_mem_full = encode_state & RMT_ENCODING_MEM_FULL; + bool need_eof_mark = (encode_state & RMT_ENCODING_WITH_EOF) == 0; if (encode_state & RMT_ENCODING_COMPLETE) { - bool need_eof_mark = (encode_state & RMT_ENCODING_WITH_EOF) == 0; // inserting EOF symbol if there's extra space - if (!(encode_state & RMT_ENCODING_MEM_FULL)) { + if (!is_mem_full) { encoded_symbols += rmt_tx_mark_eof(tx_chan, need_eof_mark); } t->flags.encoding_done = true; t->flags.need_eof_mark = need_eof_mark; } - // for loop transaction, the memory block should accommodate all encoded RMT symbols + // for loop transaction, the memory block should accommodate all encoded RMT symbols and an extra EOF symbol if (t->loop_count != 0) { - if (unlikely(encoded_symbols > tx_chan->base.mem_block_num * SOC_RMT_MEM_WORDS_PER_CHANNEL)) { + size_t limit_symbols = tx_chan->base.mem_block_num * SOC_RMT_MEM_WORDS_PER_CHANNEL; + if (unlikely(encoded_symbols > limit_symbols || (encoded_symbols == limit_symbols && is_mem_full && need_eof_mark))) { ESP_DRAM_LOGE(TAG, "encoding artifacts can't exceed hw memory block for loop transmission"); } } diff --git a/docs/en/api-reference/peripherals/rmt.rst b/docs/en/api-reference/peripherals/rmt.rst index 7d8777a471..47c5460594 100644 --- a/docs/en/api-reference/peripherals/rmt.rst +++ b/docs/en/api-reference/peripherals/rmt.rst @@ -256,7 +256,7 @@ Once you created an encoder, you can initiate a TX transaction by calling :cpp:f .. note:: - There is a limitation in the transmission size if the :cpp:member:`rmt_transmit_config_t::loop_count` is set to non-zero, i.e., to enable the loop feature. The encoded RMT symbols should not exceed the capacity of the RMT hardware memory block size, or you might see an error message like ``encoding artifacts can't exceed hw memory block for loop transmission``. If you have to start a large transaction by loop, you can try either of the following methods. + There is a limitation in the transmission size if the :cpp:member:`rmt_transmit_config_t::loop_count` is set to non-zero, i.e., to enable the loop feature. The total amount of symbols returned by the encoder should not exceed the capacity of :c:macro:`SOC_RMT_MEM_WORDS_PER_CHANNEL`, or you might see an error message like ``encoding artifacts can't exceed hw memory block for loop transmission``. If you have to start a large transaction by loop, you can try either of the following methods. - Increase the :cpp:member:`rmt_tx_channel_config_t::mem_block_symbols`. This approach does not work if the DMA backend is also enabled. - Customize an encoder and construct an infinite loop in the encoding function. See also :ref:`rmt-rmt-encoder`. diff --git a/docs/zh_CN/api-reference/peripherals/rmt.rst b/docs/zh_CN/api-reference/peripherals/rmt.rst index 652d18063e..bed0d1bafc 100644 --- a/docs/zh_CN/api-reference/peripherals/rmt.rst +++ b/docs/zh_CN/api-reference/peripherals/rmt.rst @@ -256,7 +256,7 @@ RMT 是一种特殊的通信外设,无法像 SPI 和 I2C 那样发送原始字 .. note:: - 如果将 :cpp:member:`rmt_transmit_config_t::loop_count` 设置为非零值,即启用循环功能,则传输的大小将受到限制。编码的 RMT 符号不应超过 RMT 硬件内存块容量,否则会出现类似 ``encoding artifacts can't exceed hw memory block for loop transmission`` 的报错信息。如需通过循环启动大型事务,请尝试以下任一方法: + 如果将 :cpp:member:`rmt_transmit_config_t::loop_count` 设置为非零值,即启用循环功能,则传输的大小将受到限制。编码器返回的符号总量不能超过 :c:macro:`SOC_RMT_MEM_WORDS_PER_CHANNEL`,否则会出现类似 ``encoding artifacts can't exceed hw memory block for loop transmission`` 的报错信息。如需通过循环启动大型事务,请尝试以下任一方法: - 增加 :cpp:member:`rmt_tx_channel_config_t::mem_block_symbols`。若此时启用了 DMA 后端,该方法将失效。 - 自定义编码器,并在编码函数中构造一个无限循环,详情请参阅 :ref:`rmt-rmt-encoder`。