
M E M O R Y C O N T R O L L E R
Address connectivity
222
Hardware Reference NS9215
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A d d r e s s c o n n e c t i v i t y
Memory banks
constructed from
8-bit or non-byte-
partitioned
memory devices
For memory banks constructed from 8-bit or non-byte-partitioned memory devices,
it is important that the byte lane state (PB) bit is cleared to 0 within the respective
memory bank control register. This forces all
data_mask
lines high during a read
access, as the byte lane selects are connected to the device write enables.
The next figure shows 8-bit memory configuring memory banks that are 8-, 16-, and
32-bits wide. In each of these configurations, the
data_mask[3:0]
signals are connected
to write enable (
WE_n
) inputs of each 8-bit memory. The
st_we_n
signal from the
memory controller is not used.
For write transfers, the appropriate
data_mask[3:0]
byte lane signals are asserted
low, and direct the data to the addressed bytes.
For read transfers, all
data_mask[3:0]
signals are deasserted high, enabling the
external bus to be defined for at least the width of the accessed memory.
32-bit bank consisting of four 8-bit devices
16-bit bank consisting of two 8-bit devices
A[20:0]
CE_n
OE_n
WE_n
IO[7:0]
8-bit bank consisting of one 8-bit device
addr[22:2]
cs[n]
st_oe_n
A[20:0]
CE_n
OE_n
WE_n
IO[7:0]
data_mask[3]
data[31:24]
A[20:0]
CE_n
OE_n
WE_n
IO[7:0]
data_mask[2]
data[23:16]
A[20:0]
CE_n
OE_n
WE_n
IO[7:0]
data_mask[1]
data[15:8]
A[20:0]
CE_n
OE_n
WE_n
IO[7:0]
data_mask[0]
data[7:0]
addr[21:1]
cs[n]
st_oe_n
A[20:0]
CE_n
OE_n
WE_n
IO[7:0]
data_mask[3]
data[31:24]
data_mask[2]
data[23:16]
A[20:0]
CE_n
OE_n
WE_n
IO[7:0]
data_mask[3]
data[31:24]
st_oe_n
addr[20:0]
cs[n]
Содержание NS9215
Страница 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
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Страница 4: ......
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...