
. . . . .
M E M O R Y C O N T R O L L E R
Bus turnaround
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219
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B u s t u r n a r o u n d
The memory controller can be configured for each memory bank to use external bus
turnaround cycles between read and write memory accesses. The
WAITTURN
field
can be programmed for 1 to 16 turnaround wait states, to avoid bus contention on
the external memory databus. Bus turnaround cycles are generated between
external bus transfers as follows:
Read to read (different memory banks)
Read to write (same memory bank)
Read to write (different memory banks)
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B u s t u r n a r o u n d : T i m i n g a n d p a r a m e t e r s
This section shows bus turnaround timing diagrams and parameters.
Read followed by
write with no
turnaround
This diagram shows a zero wait read followed by a zero wait write with default
turnaround between the transfers of two cycles because of the timing of the AHB
transfers. Standard AHB wait states are added to the transfers, five for the read and
three for the write.
Timing parameter
Value
WAITRD
0
WAITOEN
0
WAITPAGE
N/A
WAITWR
0
WAITWEN
0
WAITTURN
0
B
A
0
D(A)
D(B)
clk_out
addr
data
st_oe_n
cs[n]
st_we-n
Содержание NS9215
Страница 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
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Страница 26: ...26 Hardware Reference NS9215...
Страница 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Страница 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Страница 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Страница 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Страница 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...
Страница 260: ...M E MO R Y C O N T ROL L E R StaticMemory Turn Round Delay 0 3 registers 260 Hardware Reference NS9215...
Страница 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Страница 362: ...A E S D AT A E N C R Y P T I O N D E C R Y P T I O N M O D U L E CCM mode 362 Hardware Reference NS9215...
Страница 384: ...I O HU B M OD UL E Module Direct Mode TX Data Last FIFO 384 Hardware Reference NS9215 31 March 2008...
Страница 414: ...S E R I A L C ON T RO L M O D U L E U ART UART Modem Status register 414 Hardware Reference NS9215...
Страница 446: ...S E R I A L C ON T RO L M O D U L E S PI SPI timing characteristics 446 Hardware Reference NS9215...
Страница 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...
Страница 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Страница 514: ...PA CKA GING Processor Dimensions 514 Hardware Reference NS9215 P r o c e s s o r D i m e n s i o n s...
Страница 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Страница 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...