rmt多路同时发送遇到问题

[kevinshq]

已知：ESP32的RMT不支持sync manager
期望：8个信道能够排队正常发送数据，8个通道操作共计488个灯花费的时间不应明显超过一个通道操作的时间。最好是能并行发，不要求完全同步
结果：发送数据紊乱，或者需要加延迟（测试超过5ms，10ms延迟可用）才能正常亮灯，但时间不满足期望，不如一个通道控制

如下操作也尝试修改过RMT ISR IRAM-Safe，无影响。不知道是哪里的问题，有同时使用多信道控制WS2812B的朋友，欢迎讨论。

程序主要参考examples\peripherals\rmt\led_strip修改而来，核心发送数据的代码如下（LED_NUMBERS=61）：

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1.         ESP_LOGI(TAG, "rmt_transmit data.");
2.         for (int i=0; i<LED_ROWS; i++) {
3.             ESP_ERROR_CHECK(rmt_transmit(tx_channels[i], led_encoder, led_strip_pixels[i], LED_NUMBERS*sizeof(GRB), &tx_config));
4.             // vTaskDelay(pdMS_TO_TICKS(10));
5.         }
6.         vTaskDelay(pdMS_TO_TICKS(200));
7.         memset(led_strip_pixels, 0, LED_ROWS*LED_NUMBERS*sizeof(GRB));
8.         ESP_LOGI(TAG, "rmt_transmit 0.");
9.         for (int i=0; i<LED_ROWS; i++) {
10.             ESP_ERROR_CHECK(rmt_transmit(tx_channels[i], led_encoder, led_strip_pixels[i], LED_NUMBERS*sizeof(GRB), &tx_config));
11.             // vTaskDelay(pdMS_TO_TICKS(10));
12.         }
13.         vTaskDelay(pdMS_TO_TICKS(200));

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输出如下就没有了（卡住了）：

Code: [Select all] [Expand/Collapse]

1. I (463) EOAL: Install led strip encoder
2. I (473) EOAL: Start LED rainbow chase
3. I (473) EOAL: rmt_transmit data.
4. I (683) EOAL: rmt_transmit 0.

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将ESP_LOGI修改到循环内部，rmt_transmit函数的上面，输出如下：

Code: [Select all] [Expand/Collapse]

1. I (463) EOAL: Install led strip encoder
2. I (473) EOAL: Start LED rainbow chase
3. I (473) EOAL: rmt_transmit data tx_channels: 0.
4. I (483) EOAL: rmt_transmit data tx_channels: 1.
5. I (483) EOAL: rmt_transmit data tx_channels: 2.
6. I (493) EOAL: rmt_transmit data tx_channels: 3.
7. I (493) EOAL: rmt_transmit data tx_channels: 4.
8. I (503) EOAL: rmt_transmit data tx_channels: 5.
9. I (503) EOAL: rmt_transmit data tx_channels: 6.
10. I (513) EOAL: rmt_transmit data tx_channels: 7.
11. I (713) EOAL: rmt_transmit 0 tx_channels: 0.
12. I (713) EOAL: rmt_transmit 0 tx_channels: 1.
13. I (713) EOAL: rmt_transmit 0 tx_channels: 2.
14. I (713) EOAL: rmt_transmit 0 tx_channels: 3.
15. I (713) EOAL: rmt_transmit 0 tx_channels: 4.
16. I (723) EOAL: rmt_transmit 0 tx_channels: 5.
17. I (723) EOAL: rmt_transmit 0 tx_channels: 6.
18. I (733) EOAL: rmt_transmit 0 tx_channels: 7.
19. ...循环输出

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但是0、1信道灯亮的情况不符合预期，观察输出左边的时间，后面几个信道的输出符合预期，但是有点像是有了延迟后得到的效果，不可接受。
rmt_transmit函数内加了三处ESP_LOGI后部分输出如下：

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1. I (2713) rmt: acquire one transaction description from ready_queue or done_queue
2. I (2713) rmt: send the transaction descriptor to queue
3. I (2713) rmt: rmt_ll_enable_interrupt
4. I (2723) EOAL: rmt_transmit data tx_channels: 1.
5. I (2723) rmt: acquire one transaction description from ready_queue or done_queue
6. I (2733) rmt: send the transaction descriptor to queue
7. I (2743) rmt: rmt_ll_enable_interrupt
8. I (2743) EOAL: rmt_transmit data tx_channels: 2.
9. I (2753) rmt: acquire one transaction description from ready_queue or done_queue
10. I (2753) rmt: send the transaction descriptor to queue
11. I (2763) rmt: rmt_ll_enable_interrupt
12. I (2763) EOAL: rmt_transmit data tx_channels: 3.
13. I (2773) rmt: acquire one transaction description from ready_queue or done_queue
14. I (2783) rmt: send the transaction descriptor to queue
15. I (2783) rmt: rmt_ll_enable_interrupt
16. I (2793) EOAL: rmt_transmit data tx_channels: 4.
17. I (2793) rmt: acquire one transaction description from ready_queue or done_queue
18. I (2803) rmt: send the transaction descriptor to queue
19. I (2813) rmt: rmt_ll_enable_interrupt
20. I (2813) EOAL: rmt_transmit data tx_channels: 5.
21. I (2823) rmt: acquire one transaction description from ready_queue or done_queue
22. I (2833) rmt: send the transaction descriptor to queue
23. I (2833) rmt: rmt_ll_enable_interrupt
24. I (2843) EOAL: rmt_transmit data tx_channels: 6.
25. I (2843) rmt: acquire one transaction description from ready_queue or done_queue
26. I (2853) rmt: send the transaction descriptor to queue
27. I (2853) rmt: rmt_ll_enable_interrupt
28. I (2863) EOAL: rmt_transmit data tx_channels: 7.
29. I (2863) rmt: acquire one transaction description from ready_queue or done_queue
30. I (2873) rmt: send the transaction descriptor to queue
31. I (2883) rmt: rmt_ll_enable_interrupt
32. I (3083) EOAL: rmt_transmit 0 tx_channels: 0.

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程序正常运行，但是实际和下面加了延迟的效果类似，不可接受。
取消最上面代码对延迟的注释，运行输出如下：

Code: [Select all] [Expand/Collapse]

1. I (463) EOAL: Install led strip encoder
2. I (473) EOAL: Start LED rainbow chase
3. I (473) EOAL: rmt_transmit data.
4. I (763) EOAL: rmt_transmit 0.
5. ...循环输出

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程序运行正常，但是加了延迟不可接受。

[ESP_Eavo]

ESP32 不支持同步发送。硬件不支持的，软件没法保证模拟做到同步。