Universal Serial Bus OTG Controller
UG0331 User Guide Revision 15.0
349
10.3.10.12EPx_RX_INTERVAL_REG Bit Definitions
10.3.10.13EPx_FIFO_SIZE_REG Bit Definitions
[5:4]
EPx_Protocol
0
The Cortex-M3 processor (or fabric master) should set this to select the
required protocol for the receive endpoint:.
00: Control
01: ISO
10: Bulk
11: Interrupt
[3:0]
EPx_Target Endpoint
Number
0
The Cortex-M3 processor (or fabric master) should set this value to the
endpoint number contained in the receive endpoint descriptor returned
to the USB controller during device enumeration.
Table 282 •
EPx_RX_INTERVAL_REG
Bit
Number Name
Reset
Value
Function
[7:0]
EPx_Rx Polling Interval /
NAK Limit (m)
0
Defines the polling interval receive endpointx for interrupt and ISO
transfers. For bulk endpoints, this register sets the number of
frames/microframes after which the endpoint should timeout on
receiving stream of NAK responses.
The value that is set defines a number of frames/microframes (high
speed transfers), as given in
Table 283 •
EPx_FIFO_SIZE_REG
Bit
Number Name
Reset
Value
Function
[7:4]
EPx_Rx FIFO Size
N/A
Returns the sizes of the FIFOs associated with endpointx. The lower
nibble, [3:0], encodes the size of the transmit FIFO; the upper nibble,
[7:4], encodes the size of the receive endpoint FIFO. Values of 3 – 13
correspond to a FIFO size of 2n bytes (8 – 8192 bytes). If an endpoint
has not been configured, a value of 0 will be displayed. When the
transmit and receive endpoints share the same FIFO, the Rx FIFO size
will be encoded as 0xF.
The register only has this interpretation when the Index register is set to
select one of endpoints 1 – 15 and dynamic sizing is not selected. It has
a special interpretation when the INDEX_REG is set to select endpoint
0; the result returned is not valid where dynamic FIFO sizing is used.
[3:0]
EPx_Tx FIFO Size
N/A
Table 281 •
EPx_RX_TYPE_REG
(continued)
Bit
Number Name
Reset
Value
Function