CHAPTER 6 DMA FUNCTIONS (DMA CONTROLLER)
User’s Manual U12688EJ4V0UM00
181
6.6
Transfer Types
6.6.1 Two-cycle transfer
In two-cycle transfer, data transfer is performed in two-cycles, source to DMAC then DMAC to destination.
In the first cycle, the source address is output to perform reading from the source to DMAC. In the second cycle,
the destination address is output to perform writing from DMAC to the destination.
Figure 6-7 shows examples of two-cycle transfer.
Note that caution is required when in two-cycle transfer. For details, refer to 6.19 Precautions.
Figure 6-7. Timing of Two-Cycle Transfer (1/4)
(a) Block transfer mode (SRAM
→
→
→
→
DRAM)
TI
TI
TI
TI
WAIT
IOWR
IORD
LWR/LCAS
UWR/UCAS
OE
RD
BCYST
DRAM area
CSj/RASj
A0 to A23
D0 to D15
CLKOUT
DMARQn
DMAAKn
TCn
Internal DMA
request signal
BCU states
DMAC states
T1
T1R
T1
T1W
T2
T2R
T1
T1R
TO1
T1W
TO2
T2W
TW
T2R
T2
T2R
T2
T2W
T3
T2W
T0
TE
TI
SRAM area
CSk/RASk
WE
Data
Data
Data
Data
Address
Column address
Address
Column address
Row
address
Remarks 1. The circles indicate the sampling timing.
2. Broken lines indicate high impedance.
3. n = 0 to 3
j = 0 to 7, k = 0 to 7 (However, j
≠
k.)
Содержание V850E/MS1 UPD703100
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