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The following registers configure a data endpoint in response to commands received from
the USB host. For details on any of these registers, see the Am186™CC/CH/CU
Microcontrollers Register Set Manual , order #21916.
Endpoint Definition 1 (xEPDEF1):
– Based on the SET_CONFIGURATION command, the device software should write
the EP_CFG field in the xEPDEF1 register.
– Based on the SET_INTERFACE command, the device software should write the
EP_INT and EP_ASET fields in the xEPDEF1 register.
– The Endpoint number should be configured through the EP_NUM field in the xEPDEF1
register.
– Endpoint direction and Endpoint type should be configured through the EP_DIR and
EP_TYPE fields, respectively.
Endpoint Definition 2 (xEPDEF2):
FIFO size and endpoint maximum packet value fields can be programmed. The values
depend on the endpoint type selection. (Endpoint A and B FIFOs can be 8 or 16 bytes.
Endpoint C and D FIFOs can be 8, 16, 32, or 64 bytes.)
Endpoint Definition 3 (xEPDEF3):
– Based on application requirements, the appropriate interrupt mask and stop mask
fields are programmable.
– The MODE field can configure the endpoint. This determines how the endpoint
interfaces with system memory or another peripheral's data port.
– To enable the auto rate feature, use the AUTO_RATE_EN field. Note that this feature
only applies to an endpoint that is configured as an isochronous IN endpoint and
interfaces with a DMA mode. This feature requires additional programming in the
Isochronous Synchronization Control (ISCTL) register. For more information, see
"Isochronous Transfer Features" on page 18-24.
Endpoint Received Packet Size (xEPSIZ):
This is a status register that provides information on the size of the received packet (in
bytes) when the endpoint is configured for the OUT direction.
Endpoint Buffer Status (xEPBUFS):
This is a status register that provides information on the number of bytes, if any, is in the
endpoint FIFO.
Endpoint Data Port (xEPDAT):
Device software or the DMA controller uses this register to read/write to the endpoint
FIFO. A valid access to this register increments the address pointer.
Endpoint Receive Data Port Peek (xRCVPK):
Debug or emulator software uses this register to read the endpoint data FIFO without
advancing the address pointer. It is only applicable for the OUT direction.
Am186™CC/CH/CU Microcontrollers User's Manual
Universal Serial Bus (USB)
18-13
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