ATSAM3U-EK Atmel, ATSAM3U-EK Datasheet - Page 953

• Manufacturer Part Number: ATSAM3U-EK
• Description: KIT EVAL FOR AT91SAM3U CORTEX
• Manufacturer: Atmel
• Type: MCUr

Specifications of ATSAM3U-EK

• Contents: Board
• Processor To Be Evaluated: SAM3U
• Data Bus Width: 32 bit
• Interface Type: RS-232, USB
• Operating Supply Voltage: 3 V
• Silicon Manufacturer: Atmel
• Core Architecture: ARM
• Core Sub-architecture: Cortex - M3
• Silicon Core Number: SAM3U4E
• Silicon Family Name: SAM3U
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT91SAM3U
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

39.6.8.2
Figure 39-6. NYET Example with Two Endpoint Banks
39.6.8.3
39.6.8.4
6430D–ATARM–25-Mar-11
6430D–ATARM–25-Mar-11
t = 0
data 0 ACK
Data IN
Bulk IN or Interrupt IN
NYET
Bank 1
Bank 0
t = 125 μs
E
F
Thus, firmware must detect RX_SETUP polling UDPHS_EPTSTAx or catching an interrupt, read
the setup packet in the FIFO, then clear the RX_SETUP bit in the UDPHS_EPTCLRSTA register
to acknowledge the setup stage.
If STALL_SNT was set to 1, then this bit is automatically reset when a setup token is detected by
the device. Then, the device still accepts the setup stage. (See
page
NYET is a High Speed only handshake. It is returned by a High Speed endpoint as part of the
PING protocol.
High Speed devices must support an improved NAK mechanism for Bulk OUT and control end-
points (except setup stage). This mechanism allows the device to tell the host whether it has
sufficient endpoint space for the next OUT transfer (see USB 2.0 spec 8.5.1 NAK Limiting via
Ping Flow Control).
The NYET/ACK response to a High Speed Bulk OUT transfer and the PING response are auto-
matically handled by hardware in the UDPHS_EPTCTLx register (except when the user wants to
force a NAK response by using the NYET_DIS bit).
If the endpoint responds instead to the OUT/DATA transaction with an NYET handshake, this
means that the endpoint accepted the data but does not have room for another data payload.
The host controller must return to using a PING token until the endpoint indicates it has space
available.
Data IN packets are sent by the device during the data or the status stage of a control transfer or
during an (interrupt/bulk/isochronous) IN transfer. Data buffers are sent packet by packet under
the control of the application or under the control of the DMA channel.
There are three ways for an application to transfer a buffer in several packets over the USB:
• packet by packet (see
•
• DMA (see
data 1 NYET
64
964).
KB (see
Bank 1
Bank 0
t = 250 μs
E'
F
39.6.8.6
39.6.8.5
Bank 1
Bank 0
PING ACK
F
E
below)
below)
39.6.8.5
t = 375 μs
Bank 1
Bank 0
data 0 NYET
below)
F
E
Bank 1
Bank 0
t = 500 μs
F
F
PING NACK
Bank 1
Bank 0
E'
F
t = 625 μs
Bank 1
Bank 0
Section 39.6.8.15 “STALL” on
PING ACK
SAM3U Series
SAM3U Series
E
F
E: empty
E': begin to empty
F: full
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