ATSAM3U-EK Atmel, ATSAM3U-EK Datasheet - Page 955

• 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

39.6.8.6
6430D–ATARM–25-Mar-11
6430D–ATARM–25-Mar-11
Bulk IN or Interrupt IN: Sending a Buffer Using DMA (Device to Host)
The UDPHS integrates a DMA host controller. This DMA controller can be used to transfer a buf-
fer from the memory to the DPR or from the DPR to the processor memory under the UDPHS
control. The DMA can be used for all transfer types except control transfer.
Example DMA configuration:
The auto-valid-bank mechanism allows the transfer of data (IN & OUT) without the intervention
of the CPU. This means that bank validation (set TX_PK_RDY or clear the RX_BK_RDY bit) is
done by hardware.
A transfer descriptor can be used. Instead of programming the register directly, a descriptor
s h o u l d b e p r o g r a m m e d a n d t h e a d d r e s s o f t h i s d e s c r i p t o r i s t h e n g i v e n t o
UDPHS_DMANXTDSC to be processed after setting the LDNXT_DSC field (Load Next Descrip-
tor Now) in UDPHS_DMACONTROLx register.
The structure that defines this transfer descriptor must be aligned.
Each buffer to be transferred must be described by a DMA Transfer descriptor (see
DMA Channel Transfer Descriptor” on page
executing transfer of the buffer, the UDPHS may fetch a new transfer descriptor from the mem-
ory address pointed by the UDPHS_DMANXTDSCx register. Once the transfer is complete, the
transfer status is updated in the UDPHS_DMASTATUSx register.
To chain a new transfer descriptor with the current DMA transfer, the DMA channel must be
stopped. To do so, INTDIS_DMA and TX_BK_RDY may be set in the UDPHS_EPTCTLENBx
register. It is also possible for the application to wait for the completion of all transfers. In this
case the LDNXT_DSC field in the last transfer descriptor UDPHS_DMACONTROLx register
must be set to 0 and CHANN_ENB set to 1.
Then the application can chain a new transfer descriptor.
The INTDIS_DMA can be used to stop the current DMA transfer if an enabled interrupt is trig-
gered. This can be used to stop DMA transfers in case of errors.
The application can be notified at the end of any buffer transfer (ENB_BUFFIT bit in the
UDPHS_DMACONTROLx register).
1. Program UDPHS_DMAADDRESS x with the address of the buffer that should be
2. Enable the interrupt of the DMA in UDPHS_IEN
3. Program UDPHS_ DMACONTROLx:
transferred.
– Size of buffer to send: size of the buffer to be sent to the host.
– END_B_EN: The endpoint can validate the packet (according to the values
– END_BUFFIT: generate an interrupt when the BUFF_COUNT in
– CHANN_ENB: Run and stop at end of buffer
programmed in the AUTO_VALID and SHRT_PCKT fields of UDPHS_EPTCTLx.)
(See
with
UDPHS_DMASTATUSx reaches 0.
DMA)
“UDPHS Endpoint Control Register” on page 993
1004). Transfer descriptors are chained. Before
and
Figure 39-11. Autovalid
SAM3U Series
SAM3U Series
“UDPHS
955
955