
. . . . .
M E M O R Y C O N T R O L L E R
Address connectivity
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223
Memory banks
constructed from
16-or 32-bit
memory devices
For memory banks constructed from 16- or 32-bit memory devices, it is important
that the byte lane select (PB) bit is set to 1 within the respective memory bank
control register. This asserts all
data_mask[3:0]
lines low during a read access as,
during a read, all device bytes must be selected to avoid undriven byte lanes on the
read data value. With 16- and 32-bit wide memory devices, byte select signals exist
and must be appropriately controlled; see the next two figures.
Memory banks constructed from 16-bit memory
Memory bank constructed from 32-bit memory
The next figure shows connections for a typical memory system with different data
width memory devices.
32-bit bank consisting of two 16-bit devices
16-bit bank consisting of one 16-bit device
A[20:0]
CE_n
OE_n
WE_n
IO[15:0]
LB_n
UB_n
A[20:0]
CE_n
OE_n
WE_n
IO[15:0]
LB_n
UB_n
A[20:0]
CE_n
OE_n
WE_n
IO[15:0]
LB_n
UB_n
st_oe_n
addr[22:2]
cs[n]
st_we_n
data_mask[2]
data[31:16
data_mask[3]
data_mask[0]
data[15:0]
data_mask[1]
data_mask[2]
data[15:0]
st_oe_n
addr[21:1]
cs[n]
st_we_n
data_mask[3]
32-bit bank consisting of one 32-bit device
data_mask[2]
data[31:0]
st_oe_n
addr[22:2]
cs[n]
st_we_n
data_mask[3]
A[20:0]
CE_n
OE_n
WE_n
IO[31:0]
B[3]_n
B[2]_n
B[1]_n
B[0]_n
data_mask[1]
data_mask[0]
Содержание NS9215
Страница 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
Страница 3: ......
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...