Техническая Спецификация для Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK
Модели
AT91SAM9N12-EK
Tightly-Coupled Memory Interface
5-10
Copyright © 2001-2003 ARM Limited. All rights reserved.
ARM DDI0198D
Figure 5-3 Data side zero wait state accesses
In cycle T1, a nonsequential read request is made to address A.
In cycle T2, a nonsequential word write request is made to address B and data is
returned for the access to A.
returned for the access to A.
In cycle T3, no request is made.
In cycle T4, a nonsequential read request is made to address C.
In cycle T5, a sequential read request is made to address C+1 and data is returned for
the access to C.
the access to C.
In cycle T6, a nonsequential byte write request is made to address D.
5.3.2
DMA access to zero wait state TCM
For DMA accesses to zero wait state memories, the TCM DMA interface can be used
which enables an alternative source of address and chip-select to be passed through to
the TCM memories without impacting timing. Figure 5-4 on page 5-11 shows the
relationship between DRDMAEN, DRDMACS, DRDMAADDR, DRADDR and
DRCS.
which enables an alternative source of address and chip-select to be passed through to
the TCM memories without impacting timing. Figure 5-4 on page 5-11 shows the
relationship between DRDMAEN, DRDMACS, DRDMAADDR, DRADDR and
DRCS.
CLK
DRCS
DRSEQ
DRADDR
A
B
C
C+1
D
DRRD
D(A)
D(C)
D(C+1)
T1
T2
T3
T4
T5
T6
T7
DnRW
DRWD
D(B)
D(D)
DRWBL
0000
1111
0000
0001