
. . . . .
M E M O R Y C O N T R O L L E R
Byte lane control
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221
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B y t e l a n e c o n t r o l
The memory controller generates the byte lane control signals
data_mask[3:0]
according to these attributes:
Little or big endian operation
Transfer width
External memory bank databus width, defined within each control register
The decoded
address
value for write accesses only
Word transfers are the largest size transfers supported by the memory controller.
Any access tried with a size greater that a word causes an error response. Each
memory chip select can be 8, 16, or 32 bits wide. The memory type used
determines how the
st_we_n
and
data_mask
signals are connected to provide byte,
halfword, and word access.
For read accesses, you must control the
data_mask
signals by driving them all high or
all low. Do this by programming the byte lane state (PB) bit in the Static
Configuration [3:0] register. See “Address connectivity” on page 222 for additional
information, with respect to
st_we_n
and
data_mask
, for different memory
configurations.
Timing parameters
Value
WAITRD
0
WAITOEN
0
WAITPAGE
N/A
WAITWR
0
WAITWEN
0
WAITTURN
2
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...