
E X T E R N A L D M A
Peripheral REQ and DONE signaling
344
Hardware Reference NS9215
Determining the
width of PDEN
Use the memory controller’s Static Memory Write Delay register and Static Memory
Write Enable Delay register to determine the width of the PDEN assertion.
Peripheral DMA
single write access
Peripheral DMA
burst write access
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
P e r i p h e r a l R E Q a n d D O N E s i g n a l i n g
The processor treats the REQ and DONE signals as asynchronous, level signals.
REQ signal
The external peripheral can initiate a DMA transfer at any time by asserting the
REQ signal.
The external peripheral can pause the DMA transfer at any time by deasserting
the REQ signal.
The REQ signal can be deasserted during a transfer but if the peripheral is
configured for burst access, the burst completes. The DMA transfer control
logic remains paused until the REQ signal is reasserted.
ADDR &
DATA
st_cs_n[
n
]
CLK
we_n
Addr/Data Valid
PDEN
CLK
ADDR0/DATA0
st_cs_n[
n
]
we_n
ADDR &
DATA
ADDR1/DATA1
ADDR2/DATA2
PDEN
Summary of Contents for NS9215
Page 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
Page 3: ......
Page 4: ......
Page 26: ...26 Hardware Reference NS9215...
Page 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Page 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Page 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Page 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Page 202: ...S Y S T E M C O N T RO L M OD U L E RTC Module Control register 202 Hardware Reference NS9215...
Page 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Page 472: ...R E A L TI M E C L O C K M O D U L E General Status register 472 Hardware Reference NS9215...
Page 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Page 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Page 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...