AT91SAM9G45-EKES Atmel, AT91SAM9G45-EKES Datasheet - Page 835

• Manufacturer Part Number: AT91SAM9G45-EKES
• Description: KIT EVAL FOR AT91SAM9G45
• Manufacturer: Atmel
• Series: AT91SAM Smart ARMr
• Type: MCUr

Specifications of AT91SAM9G45-EKES

• Contents: Board
• Processor To Be Evaluated: SAM9G45
• Data Bus Width: 32 bit
• Interface Type: I2C, SPI, UART
• Maximum Operating Temperature: + 50 C
• Minimum Operating Temperature: - 10 C
• Operating Supply Voltage: 1.8 V to 3.3 V
• For Use With/related Products: AT91SAM9G45
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: Q4626953

38.5.8.2
Figure 38-7. NYET Example with Two Endpoint Banks
38.5.8.3
38.5.8.4
38.5.8.5
835
t = 0
data 0 ACK
AT91SAM9G45
NYET
Data IN
Bulk IN or Interrupt IN
Bulk IN or Interrupt IN: Sending a Packet Under Application Control (Device to Host)
Bank 1
Bank 0
t = 125 μs
E
F
data 1 NYET
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:
The application can write one or several banks.
• packet by packet (see
•
• DMA (see
Bank 1
Bank 0
64
846).
KB (see
t = 250 μs
E'
F
Bank 1
Bank 0
PING ACK
38.5.8.6
38.5.8.5
F
E
below)
t = 375 μs
below)
38.5.8.5
Bank 1
Bank 0
data 0 NYET
F
E
below)
Bank 1
Bank 0
t = 500 μs
F
F
PING NACK
Bank 1
Bank 0
E'
F
t = 625 μs
Bank 1
Bank 0
PING ACK
Section 38.5.8.15 “STALL” on
E
F
E: empty
E': begin to empty
F: full
6438F–ATARM–21-Jun-10