From c6e7e825247741501f4028e2fea5391b6fe8ab51 Mon Sep 17 00:00:00 2001 From: laokaiyao Date: Mon, 9 Sep 2024 15:10:34 +0800 Subject: [PATCH] change(sdm): delete the confusing part in sdm programming guide --- components/hal/esp32/include/hal/sdm_ll.h | 3 ++- components/hal/esp32c3/include/hal/sdm_ll.h | 3 ++- components/hal/esp32c5/include/hal/sdm_ll.h | 3 ++- components/hal/esp32c6/include/hal/sdm_ll.h | 3 ++- components/hal/esp32h2/include/hal/sdm_ll.h | 3 ++- components/hal/esp32p4/include/hal/sdm_ll.h | 3 ++- components/hal/esp32s2/include/hal/sdm_ll.h | 3 ++- components/hal/esp32s3/include/hal/sdm_ll.h | 3 ++- docs/en/api-reference/peripherals/sdm.rst | 9 ++------- docs/zh_CN/api-reference/peripherals/sdm.rst | 9 ++------- 10 files changed, 20 insertions(+), 22 deletions(-) diff --git a/components/hal/esp32/include/hal/sdm_ll.h b/components/hal/esp32/include/hal/sdm_ll.h index 4708a33534..45bd8a4067 100644 --- a/components/hal/esp32/include/hal/sdm_ll.h +++ b/components/hal/esp32/include/hal/sdm_ll.h @@ -10,12 +10,13 @@ #include "hal/misc.h" #include "hal/assert.h" #include "soc/gpio_sd_struct.h" +#include "soc/gpio_sd_reg.h" #ifdef __cplusplus extern "C" { #endif -#define SDM_LL_PRESCALE_MAX 256 +#define SDM_LL_PRESCALE_MAX (GPIO_SD0_PRESCALE_V + 1) /** * @brief Set Sigma-delta enable diff --git a/components/hal/esp32c3/include/hal/sdm_ll.h b/components/hal/esp32c3/include/hal/sdm_ll.h index 97cf7669dd..70071812a3 100644 --- a/components/hal/esp32c3/include/hal/sdm_ll.h +++ b/components/hal/esp32c3/include/hal/sdm_ll.h @@ -10,12 +10,13 @@ #include "hal/misc.h" #include "hal/assert.h" #include "soc/gpio_sd_struct.h" +#include "soc/gpio_sd_reg.h" #ifdef __cplusplus extern "C" { #endif -#define SDM_LL_PRESCALE_MAX 256 +#define SDM_LL_PRESCALE_MAX (GPIO_SD0_PRESCALE_V + 1) /** * @brief Set Sigma-delta enable diff --git a/components/hal/esp32c5/include/hal/sdm_ll.h b/components/hal/esp32c5/include/hal/sdm_ll.h index 4f86a309d4..c73e06cb92 100644 --- a/components/hal/esp32c5/include/hal/sdm_ll.h +++ b/components/hal/esp32c5/include/hal/sdm_ll.h @@ -10,12 +10,13 @@ #include "hal/misc.h" #include "hal/assert.h" #include "soc/gpio_ext_struct.h" +#include "soc/gpio_ext_reg.h" #ifdef __cplusplus extern "C" { #endif -#define SDM_LL_PRESCALE_MAX 256 +#define SDM_LL_PRESCALE_MAX (GPIO_EXT_SD0_PRESCALE_V + 1) /** * @brief Set Sigma-delta enable diff --git a/components/hal/esp32c6/include/hal/sdm_ll.h b/components/hal/esp32c6/include/hal/sdm_ll.h index 621ddf3672..e2da68b485 100644 --- a/components/hal/esp32c6/include/hal/sdm_ll.h +++ b/components/hal/esp32c6/include/hal/sdm_ll.h @@ -10,12 +10,13 @@ #include "hal/misc.h" #include "hal/assert.h" #include "soc/gpio_ext_struct.h" +#include "soc/gpio_ext_reg.h" #ifdef __cplusplus extern "C" { #endif -#define SDM_LL_PRESCALE_MAX 256 +#define SDM_LL_PRESCALE_MAX (GPIO_EXT_SD0_PRESCALE_V + 1) /** * @brief Set Sigma-delta enable diff --git a/components/hal/esp32h2/include/hal/sdm_ll.h b/components/hal/esp32h2/include/hal/sdm_ll.h index 621ddf3672..e2da68b485 100644 --- a/components/hal/esp32h2/include/hal/sdm_ll.h +++ b/components/hal/esp32h2/include/hal/sdm_ll.h @@ -10,12 +10,13 @@ #include "hal/misc.h" #include "hal/assert.h" #include "soc/gpio_ext_struct.h" +#include "soc/gpio_ext_reg.h" #ifdef __cplusplus extern "C" { #endif -#define SDM_LL_PRESCALE_MAX 256 +#define SDM_LL_PRESCALE_MAX (GPIO_EXT_SD0_PRESCALE_V + 1) /** * @brief Set Sigma-delta enable diff --git a/components/hal/esp32p4/include/hal/sdm_ll.h b/components/hal/esp32p4/include/hal/sdm_ll.h index 621ddf3672..e2da68b485 100644 --- a/components/hal/esp32p4/include/hal/sdm_ll.h +++ b/components/hal/esp32p4/include/hal/sdm_ll.h @@ -10,12 +10,13 @@ #include "hal/misc.h" #include "hal/assert.h" #include "soc/gpio_ext_struct.h" +#include "soc/gpio_ext_reg.h" #ifdef __cplusplus extern "C" { #endif -#define SDM_LL_PRESCALE_MAX 256 +#define SDM_LL_PRESCALE_MAX (GPIO_EXT_SD0_PRESCALE_V + 1) /** * @brief Set Sigma-delta enable diff --git a/components/hal/esp32s2/include/hal/sdm_ll.h b/components/hal/esp32s2/include/hal/sdm_ll.h index be0d2d97f8..009e7e94af 100644 --- a/components/hal/esp32s2/include/hal/sdm_ll.h +++ b/components/hal/esp32s2/include/hal/sdm_ll.h @@ -10,12 +10,13 @@ #include "hal/misc.h" #include "hal/assert.h" #include "soc/gpio_sd_struct.h" +#include "soc/gpio_sd_reg.h" #ifdef __cplusplus extern "C" { #endif -#define SDM_LL_PRESCALE_MAX 256 +#define SDM_LL_PRESCALE_MAX (GPIO_SD0_PRESCALE_V + 1) /** * @brief Set Sigma-delta enable diff --git a/components/hal/esp32s3/include/hal/sdm_ll.h b/components/hal/esp32s3/include/hal/sdm_ll.h index c58724ea7a..58ec1eb469 100644 --- a/components/hal/esp32s3/include/hal/sdm_ll.h +++ b/components/hal/esp32s3/include/hal/sdm_ll.h @@ -10,12 +10,13 @@ #include "hal/assert.h" #include "hal/misc.h" #include "soc/gpio_sd_struct.h" +#include "soc/gpio_sd_reg.h" #ifdef __cplusplus extern "C" { #endif -#define SDM_LL_PRESCALE_MAX 256 +#define SDM_LL_PRESCALE_MAX (GPIO_SD0_PRESCALE_V + 1) /** * @brief Set Sigma-delta enable diff --git a/docs/en/api-reference/peripherals/sdm.rst b/docs/en/api-reference/peripherals/sdm.rst index faa5bd9ddf..85edb53f73 100644 --- a/docs/en/api-reference/peripherals/sdm.rst +++ b/docs/en/api-reference/peripherals/sdm.rst @@ -10,12 +10,6 @@ Introduction Delta-sigma modulation converts an analog voltage signal into a pulse frequency, or pulse density, which can be understood as pulse-density modulation (PDM) (refer to |wiki_ref|_). -The main differences comparing to I2S PDM mode and DAC peripheral are: - -1. SDM has no clock signal, it is just like the DAC mode of PDM; -2. SDM has no DMA, and it can not change its output density continuously. If you have to, you can update the density in a timer's callback; -3. Based on the former two points, unlike the DAC peripheral, an external active or passive low-pass filter is required additionally to restore the analog wave (See :ref:`convert_to_analog_signal`). - Typically, a Sigma-Delta modulated channel can be used in scenarios like: - LED dimming @@ -46,7 +40,7 @@ To install an SDM channel, you should call :cpp:func:`sdm_new_channel` to get a - :cpp:member:`sdm_config_t::gpio_num` sets the GPIO that the PDM pulses output from. - :cpp:member:`sdm_config_t::clk_src` selects the source clock for the SDM module. Note that, all channels should select the same clock source. -- :cpp:member:`sdm_config_t::sample_rate_hz` sets the sample rate of the SDM module. +- :cpp:member:`sdm_config_t::sample_rate_hz` sets the sample rate of the SDM module. A higher sample rate can help to output signals with higher SNR (Signal to Noise Ratio), and easier to restore the original signal after the filter. - :cpp:member:`sdm_config_t::invert_out` sets whether to invert the output signal. - :cpp:member:`sdm_config_t::io_loop_back` is for debugging purposes only. It enables both the GPIO's input and output ability through the GPIO matrix peripheral. @@ -141,6 +135,7 @@ For example, you can take the following `Sallen-Key topology Low Pass Filter`_ a Sallen-Key Low Pass Filter +(Refer to :example_file:`peripherals/sigma_delta/sdm_dac/README.md` to see the waveforms before and after filtering.) Application Examples -------------------- diff --git a/docs/zh_CN/api-reference/peripherals/sdm.rst b/docs/zh_CN/api-reference/peripherals/sdm.rst index 397e995ec6..0547cd99c7 100644 --- a/docs/zh_CN/api-reference/peripherals/sdm.rst +++ b/docs/zh_CN/api-reference/peripherals/sdm.rst @@ -10,12 +10,6 @@ Sigma-Delta 调制器 (SDM) Sigma-Delta 调制器可以将模拟电压信号转换为脉冲频率或脉冲密度，该过程称为脉冲密度调制 (PDM)（请参阅 |wiki_ref|_）。 -与 I2S 外设中的 PDM 模式和和数模转换器 (DAC) 相比，SDM 中的 PDM 主要有以下特点： - -1. SDM 没有时钟信号，类似于 PDM 的 DAC 模式； -2. SDM 没有 DMA 支持，无法持续改变其输出密度。如果需要改变 SDM 的输出密度，可以在定时器的回调函数中进行操作； -3. 基于以上两点，不同于 DAC，要还原模拟波形，还必须使用外部的有源或无源低通滤波器，详情请参阅 :ref:`convert_to_analog_signal`。 - Sigma-Delta 调制通道通常应用于以下场景： - LED 调光 @@ -46,7 +40,7 @@ Sigma-Delta 调制通道通常应用于以下场景： - :cpp:member:`sdm_config_t::gpio_num` 设置 PDM 脉冲输出的 GPIO 管脚号。 - :cpp:member:`sdm_config_t::clk_src` 选择 SDM 模块的时钟源。注意，所有通道选择的时钟源应保持一致。 -- :cpp:member:`sdm_config_t::sample_rate_hz` 设置 SDM 模块的采样率。 +- :cpp:member:`sdm_config_t::sample_rate_hz` 设置 SDM 模块的采样率。提高采样率可以提高输出信号的信噪比，更容易在后级通过滤波获取高精度的原始信号。 - :cpp:member:`sdm_config_t::invert_out` 设置是否反转输出信号。 - :cpp:member:`sdm_config_t::io_loop_back` 通过 GPIO 矩阵外设，启用 GPIO 的输入和输出功能。注意，该字段仅供调试使用。 @@ -141,6 +135,7 @@ Kconfig 选项 Sallen-Key 拓扑低通滤波器 +（滤波前后的波形请参阅文档 :example_file:`peripherals/sigma_delta/sdm_dac/README.md`） 应用示例 --------