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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
175 of 571
NXP Semiconductors
UM10316
Chapter 13: LPC29xx USB device
[1]
DMA can not be enabled for this endpoint and the corresponding bit in the USBDMARSt must be 0.
9.7.2 USB DMA Request Clear register (USBDMARClr - 0xE010 C254)
Writing one to a bit in this register will clear the corresponding bit in the USBDMARSt
register. Writing zero has no effect.
This register is intended for initialization prior to enabling the DMA for an endpoint. When
the DMA is enabled for an endpoint, hardware clears the corresponding bit in
USBDMARSt on completion of a packet transfer. Therefore, software should not clear the
bit using this register while the endpoint is enabled for DMA operation.
USBDMARClr is a write only register.
The USBDMARClr bit allocation is identical to the USBDMARSt register (
).
9.7.3 USB DMA Request Set register (USBDMARSet - 0xE010 C258)
Writing one to a bit in this register sets the corresponding bit in the USBDMARSt register.
Writing zero has no effect.
Table 151. USB DMA Request Status register (USBDMARSt - address 0xE010 C250) bit allocation
Reset value: 0x0000 0000
Bit
31
30
29
28
27
26
25
24
Symbol
EP31
EP30
EP29
EP28
EP27
EP26
EP25
EP24
Bit
23
22
21
20
19
18
17
16
Symbol
EP23
EP22
EP21
EP20
EP19
EP18
EP17
EP16
Bit
15
14
13
12
11
10
9
8
Symbol
EP15
EP14
EP13
EP12
EP11
EP10
EP9
EP8
Bit
7
6
5
4
3
2
1
0
Symbol
EP7
EP6
EP5
EP4
EP3
EP2
EP1
EP0
Table 152. USB DMA Request Status register (USBDMARSt - address 0xE010 C250) bit description
Bit
Symbol
Value
Description
Reset value
0
EP0
0
Control endpoint OUT (DMA cannot be enabled for this endpoint and EP0
bit must be 0).
0
1
EP1
0
Control endpoint IN (DMA cannot be enabled for this endpoint and EP1 bit
must be 0).
0
31:2
EPxx
Endpoint xx (2
≤
xx
≤
31) DMA request.
0
0
DMA not requested by endpoint xx.
1
DMA requested by endpoint xx.
Table 153. USB DMA Request Clear register (USBDMARClr - address 0xE010 C254) bit description
Bit
Symbol
Value
Description
Reset value
0
EP0
0
Control endpoint OUT (DMA cannot be enabled for this endpoint and the
EP0 bit must be 0).
0
1
EP1
0
Control endpoint IN (DMA cannot be enabled for this endpoint and the EP1
bit must be 0).
0
31:2
EPxx
Clear the endpoint xx (2
≤
xx
≤
31) DMA request.
0
0
No effect.
1
Clear the corresponding bit in USBDMARSt.