AT91SAM9G45-EKES Atmel, AT91SAM9G45-EKES Datasheet - Page 890

• 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

38.6.21
Name:
Addresses:
Access Type:
• CHANN_ENB (Channel Enable Command)
0 = DMA channel is disabled at and no transfer will occur upon request. This bit is also cleared by hardware when the chan-
nel source bus is disabled at end of buffer.
If the UDPHS_DMACONTROL register LDNXT_DSC bit has been cleared by descriptor loading, the firmware will have to
set the corresponding CHANN_ENB bit to start the described transfer, if needed.
If the UDPHS_DMACONTROL register LDNXT_DSC bit is cleared, the channel is frozen and the channel registers may
then be read and/or written reliably as soon as both UDPHS_DMASTATUS register CHANN_ENB and CHANN_ACT flags
read as 0.
If a channel request is currently serviced when this bit is cleared, the DMA FIFO buffer is drained until it is empty, then the
UDPHS_DMASTATUS register CHANN_ENB bit is cleared.
If the LDNXT_DSC bit is set at or after this bit clearing, then the currently loaded descriptor is skipped (no data transfer
occurs) and the next descriptor is immediately loaded.
1 = UDPHS_DMASTATUS register CHANN_ENB bit will be set, thus enabling DMA channel data transfer. Then any pend-
ing request will start the transfer. This may be used to start or resume any requested transfer.
• LDNXT_DSC: Load Next Channel Transfer Descriptor Enable (Command)
0 = no channel register is loaded after the end of the channel transfer.
1 = the channel controller loads the next descriptor after the end of the current transfer, i.e. when the
UDPHS_DMASTATUS/CHANN_ENB bit is reset.
If the UDPHS_DMA CONTROL/CHANN_ENB bit is cleared, the next descriptor is immediately loaded upon transfer
request.
DMA Channel Control Command Summary
890
BURST_LCK
LDNXT_DSC
31
23
15
–
7
0
0
1
1
AT91SAM9G45
UDPHS DMA Channel Control Register
DESC_LD_IT
30
22
14
UDPHS_DMACONTROLx [x = 1..5]
0xFFF78328 [1], 0xFFF78338 [2], 0xFFF78348 [3], 0xFFF78358 [4], 0xFFF78368 [5]
Read-write
–
6
CHANN_ENB
0
1
0
1
END_BUFFIT
29
21
13
–
5
Stop now
Run and stop at end of buffer
Load next descriptor now
Run and link at end of buffer
END_TR_IT
28
20
12
–
4
BUFF_LENGTH
BUFF_LENGTH
Description
END_B_EN
27
19
11
–
3
END_TR_EN
26
18
10
–
2
LDNXT_DSC
25
17
9
–
1
6438F–ATARM–21-Jun-10
CHANN_ENB
24
16
8
–
0