STR910FAZ32H6T STMICROELECTRONICS [STMicroelectronics], STR910FAZ32H6T Datasheet - Page 31

• Manufacturer Part Number: STR910FAZ32H6T
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STR91xFAx32 STR91xFAx42 STR91xFAx44
3.18.1
3.18.2
3.18.3
3.19
The USB slave interface includes the following features:
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Packet buffer interface (PBI)
The PBI manages a set of buffers inside the 2 Kbyte Packet Buffer, both for transmission
and reception. The PBI will choose the proper buffer according to requests coming from the
USB Serial Interface Engine (SIE) and locate it in the Packet SRAM according to addresses
pointed by endpoint registers. The PBI will also auto-increment the address after each
exchanged byte until the end of packet, keeping track of the number of exchanged bytes and
preventing buffer overrun. Special support is provided by the PBI for isochronous and bulk
transfers, implementing double-buffer usage which ensures there is always an available
buffer for a USB packet while the CPU uses a different buffer.
DMA
A programmable DMA channel may be assigned by CPU firmware to service the USB
interface for fast and direct transfers between the USB bus and SRAM with little CPU
involvement. This DMA channel includes the following features:
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Suspend mode
CPU firmware may place the USB interface in a low-power suspend mode when required,
and the USB interface will automatically wake up asynchronously upon detecting activity on
the USB pins.
CAN 2.0B interface
The STR91xFA provides a CAN interface complying with CAN protocol version 2.0 parts A
and B. An external CAN transceiver device connected to pins CAN_RX and CAN_TX is
required for connection to the physical CAN bus.
The CAN interface manages up to 32 Message Objects and Identifier Masks using a
Message SRAM and a Message Handler. The Message Handler takes care of low-level
CAN bus activity such as acceptance filtering, transfer of messages between the CAN bus
Supports USB low and full-speed transfers (12 Mbps), certified to comply with the USB
2.0 specification
Supports isochronous, bulk, control, and interrupt endpoints
Configurable number of endpoints allowing a mixture of up to 20 single-buffered
monodirectional endpoints or up to 10 double-buffered bidirectional endpoints
Dedicated, dual-port 2 Kbyte USB Packet Buffer SRAM. One port of the SRAM is
connected by a Packet Buffer Interface (PBI) on the USB side, and the CPU connects
to the other SRAM port.
CRC generation and checking
NRZI encoding-decoding and bit stuffing
USB suspend resume operations
Direct USB Packet Buffer SRAM to system SRAM transfers of receive packets, by
descriptor chain for bulk or isochronous endpoints.
Direct system SRAM to USB Packet Buffer SRAM transfers of transmit packets, by
descriptor chain for bulk or isochronous endpoints.
Linked-list descriptor chain support for multiple USB packets
Functional overview
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