menu "USB-OTG" visible if IDF_TARGET_ESP32S2 || IDF_TARGET_ESP32S3 # Invisible item, enabled when USB_OTG peripheral does exist config USB_OTG_SUPPORTED bool default y if IDF_TARGET_ESP32S2 || IDF_TARGET_ESP32S3 config USB_HOST_CONTROL_TRANSFER_MAX_SIZE depends on USB_OTG_SUPPORTED int "Largest size (in bytes) of transfers to/from default endpoints" default 256 help Each USB device attached is allocated a dedicated buffer for its OUT/IN transfers to/from the device's control endpoint. The maximum size of that buffer is determined by this option. The limited size of the transfer buffer have the following implications: - The maximum length of control transfers is limited - Device's with configuration descriptors larger than this limit cannot be supported choice USB_HOST_HW_BUFFER_BIAS depends on USB_OTG_SUPPORTED prompt "Hardware FIFO size biasing" default USB_HOST_HW_BUFFER_BIAS_BALANCED help The underlying hardware has size adjustable FIFOs to cache USB packets on reception (IN) or for transmission (OUT). The size of these FIFOs will affect the largest MPS (maximum packet size) and the maximum number of packets that can be cached at any one time. The hardware contains the following FIFOS: RX (for all IN packets), Non-periodic TX (for Bulk and Control OUT packets), and Periodic TX (for Interrupt and Isochronous OUT packets). This configuration option allows biasing the FIFO sizes towards a particular use case, which may be necessary for devices that have endpoints with large MPS. The MPS limits for each biasing are listed below: Balanced: - IN (all transfer types), 408 bytes - OUT non-periodic (Bulk/Control), 192 bytes (i.e., 3 x 64 byte packets) - OUT periodic (Interrupt/Isochronous), 192 bytes Bias IN: - IN (all transfer types), 600 bytes - OUT non-periodic (Bulk/Control), 64 bytes (i.e., 1 x 64 byte packets) - OUT periodic (Interrupt/Isochronous), 128 bytes Bias Periodic OUT: - IN (all transfer types), 128 bytes - OUT non-periodic (Bulk/Control), 64 bytes (i.e., 1 x 64 byte packets) - OUT periodic (Interrupt/Isochronous), 600 bytes config USB_HOST_HW_BUFFER_BIAS_BALANCED bool "Balanced" config USB_HOST_HW_BUFFER_BIAS_IN bool "Bias IN" config USB_HOST_HW_BUFFER_BIAS_PERIODIC_OUT bool "Periodic OUT" endchoice endmenu #USB-OTG