kopia lustrzana https://github.com/espressif/esp-idf
97 wiersze
6.4 KiB
ReStructuredText
97 wiersze
6.4 KiB
ReStructuredText
PHY
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==================
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:link_to_translation:`zh_CN:[中文]`
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Multiple Antennas
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--------------------------
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Principles and Components of Multiple Antennas
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+++++++++++++++++++++++++++++++++++++++++++++++
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Multi-antenna functionality primarily involves routing signals from internal antenna modules to specific IO pins, controlling external antenna switches through IO pins to select designated antennas, supporting up to 16 antennas.
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The components of multiple antennas can be depicted as following picture::
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___________________________________________________________________________
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____|____ _________ |
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|PHY |--antenna_select[0] --> | | |
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___|Antenna 0|--antenna_select[1] --> | | |
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/ |Module |--antenna_select[2] --> | | ____|____
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/ |_________|--antenna_select[3] --> | IO MUX |--GPIO[x0] --> ant_sel_in[0]--| | --- antenna 0
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RX/TX ___/ | | And |--GPIO[x1] --> ant_sel_in[1]--| Antenna | --- antenna 1
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\ ____|____ | GPIO |--GPIO[x2] --> ant_sel_in[2]--| Switch | ... ...
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\ |PHY |--antenna_select[0] --> | Matrix |--GPIO[x3] --> ant_sel_in[3]--|_________| --- antenna 15
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\___|Antenna 1|--antenna_select[1] --> | |
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|Module |--antenna_select[2] --> | |
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|_________|--antenna_select[3] --> |_________|
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{IDF_TARGET_NAME} Multiple antennas primarily consists of three parts: the PHY Antenna Module inside the chip, IO MUX and GPIO Matrix, and external antenna switches.
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1. PHY Antenna Module:
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- Both antenna modules support operation in transmit (TX) or receive (RX) mode, and can be configured via software to select a particular module for transmission or reception.
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- Each antenna module supports outputting up to 4 antenna selection signals antenna_select[3:0], which can be configured by software and mapped to any IO pin individually.
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- When an antenna module is in operation, the logic level of the IO pin corresponds to the configured signal value.
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2. IO MUX and GPIO Matrix:
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- Routes the internal 4-way antenna signals to specific IO pins.
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3. External Antenna Switches:
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- Typically multi-way selectors, they choose the working antenna based on the logic level of the ant_sel_in[x] pin. For example, ant_sel_in[3:0] as "0b1011" selects antenna 11.
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Steps for Multi-Antenna Usage
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++++++++++++++++++++++++++++++
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1. Determine the IO pins used for controlling antenna switching based on hardware circuit design and external antenna switches.
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2. Configure antenna selection signals to output to specified IO pins.
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- API :cpp:func:`esp_phy_set_ant_gpio()` is used to configure antenna_selects[3:0] signals to connect with GPIO[x3:x0]. If GPIO[x0] is connected to antenna_select[0], gpio_config->gpio_cfg[x0].gpio_select should be set to 1, and the value of gpio_config->gpio_cfg[x0].gpio_num should be GPIO[x0].
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3. Configure internal antenna operation mode and output signals.
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- API :cpp:func:`esp_phy_set_ant()` is used to configure the use of internal antenna module 0 or 1 for transmission or reception, and to configure the output signal values when antenna module 0 or 1 is in operation.
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- ESP_PHY_ANT_MODE_AUTO mode is currently not recommended for use.
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Multi-Antenna Configuration Reference Example
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+++++++++++++++++++++++++++++++++++++++++++++++
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Typically, the following steps can be performed to configure multi-antenna:
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- Configure antenna_selects to connect with which GPIOs. For example, if four antennas are supported and GPIO20/GPIO21 are connected to antenna_select[0]/antenna_select[1], the configuration is as follows:
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.. code-block:: c
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esp_phy_ant_gpio_config_t ant_gpio_config = {
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.gpio_cfg[0] = { .gpio_select = 1, .gpio_num = 20 },
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.gpio_cfg[1] = { .gpio_select = 1, .gpio_num = 21 }
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};
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- Configure which antennas are enabled and how enabled antennas are used for receiving/sending data. For example, if antennas 1 and 3 are enabled, data reception needs to automatically select the better antenna, with antenna 1 set as the default antenna, and data transmission always selecting antenna 3. The configuration is as follows:
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.. code-block:: c
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esp_phy_ant_config_t config = {
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.rx_ant_mode = ESP_PHY_ANT_MODE_AUTO,
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.rx_ant_default = ESP_PHY_ANT_ANT0,
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.tx_ant_mode = ESP_PHY_ANT_MODE_ANT1,
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.enabled_ant0 = 1,
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.enabled_ant1 = 3
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};
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Notes
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++++++++++++++++++++++++++
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1. Different antenna switches may have invalid input values for `ant_sel_in[3:0]`, meaning the number of antennas supported by {IDF_TARGET_NAME} via external antenna switches may be less than 16. For example, ESP32-WROOM-DA uses RTC6603SP as the antenna switch, supporting only 2 antennas. The two antenna selection input pins are active high and are connected to two GPIOs. '0b01' indicates antenna 0 is selected, '0b10' indicates antenna 1 is selected. Input values '0b00' and '0b11' are invalid.
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2. Despite supporting up to 16 antennas, only a maximum of two antennas can be enabled simultaneously for sending and receiving data.
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3. The use of ESP_PHY_ANT_MODE_AUTO mode is currently not recommended, primarily due to the following limitations:
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- For the antenna selection algorithm based on ESP_PHY_ANT_MODE_AUTO type for sending data, the antenna for sending data can only be set to ESP_PHY_ANT_MODE_AUTO when the antenna mode for receiving data is ESP_PHY_ANT_MODE_AUTO.
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- When the receiving or sending antenna mode is configured as ESP_PHY_ANT_MODE_AUTO, frequent antenna switching may occur if RF signal degradation is detected. Unstable RF signals can lead to frequent antenna switching, resulting in the overall RF performance not meeting expectations.
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Recommended Scenarios for Using Multiple Antennas
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++++++++++++++++++++++++++++++++++++++++++++++++++
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1. Applications can either select specified antennas or implement their own antenna selection algorithms based on collected information, such as selecting antenna modes according to application-specific criteria. Refer to the IDF example :idf_file:`examples/phy/antenna/README.md` for designing antenna selection algorithms.
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2. Configure antenna modes for both receiving and sending data as ESP_PHY_ANT_MODE_ANT0 or ESP_PHY_ANT_MODE_ANT1.
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