STM32F101xx, STM32F102xx, STM32F103xx, STM32F105xx and ...

RM0008
USB on-the-go full-speed (OTG_FS)
26.2.1 General features
The OTG_FS interface:
● is USB-IF certified to the Universal Serial Bus Specification Rev 2.0
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includes full support (PHY) for the optional On-The-Go (OTG) protocol detailed in the
On-The-Go Supplement Rev 1.3 specification
– integrated support for A-B Device Identification (ID line)
– integrated support for Host Negotiation Protocol (HNP) and Session Request
Protocol (SRP)
– allows host to turn VBUS off to conserve battery power in OTG applications
– supports OTG monitoring of VBUS levels with internal comparators
– supports dynamic Host-Peripheral switch of role
is software-configurable to operate as:
– SRP capable USB FS Peripheral (B-Device)
– SRP capable USB FS/LS Host (A-Device)
– USB On-The-Go Full-Speed Dual Role Device
supports FS SOF and LS Keep-alives with
– SOF pulse PAD connectivity
– SOF pulse internal connection to timer2 (TIM2)
– configurable framing period
– configurable end of frame interrupt
includes power saving features such as system stop during USB Suspend, switch-off of
clock domains internal to the digital core, PHY and DFIFO power management
features a dedicated RAM of 1.25 Kbytes with advanced FIFO control:
– configurable partitioning of RAM space into different FIFOs for flexible and efficient
use of RAM
– each FIFO can hold multiple packets
– dynamic memory allocation
– configurable FIFO sizes that are not powers of 2 to allow the use of contiguous
memory locations
guarantees max USB bandwidth for up to one frame (1ms) withouth system
intervention
26.2.2 Host-mode features
The OTG_FS interface:
● requires an external charge pump to generate the V BUS voltage
● has up to 8 host channels (pipes) and each channel is dynamically reconfigurable to
allocate any type of USB transfer
● has a built-in HW scheduler holding:
– up to 8 interrupt plus isochronous transfer requests in the periodic hardware
queue
– up to 8 control plus bulk transfer requests in the non-periodic hardware queue
● manages a shared RX FIFO, a periodic TX FIFO and a nonperiodic TX FIFO for
efficient usage of the USB data RAM
Doc ID 13902 Rev 9 695/995