CHAPTER 7 DMAC
Preliminary User’s Manual A14874EJ3V0UM
192
(2) Flyby transfers
Figures 7-36 to 7-41 show examples of the timing of flyby transfers between external SRAM and external I/O
connected to the MEMC (NT85E500). The flyby transfer consists of the following states.
•
T1, T2 states: These are basic states for accessing the NT85E500.
•
T3 state:
This is a basic state added for flyby transfer.
•
TA state:
This is an address setting wait state inserted by means of a setting in the NT85E500’s ASC
register.
•
TI state:
This is an idle state inserted by means of a setting in the NT85E500’s BCC register.
•
TW state:
This is a wait state inserted by means of a setting in the NT85E500’s DWC0 register.
Remarks 1.
The levels of the broken-line portions of the VMCTYP2 to VMCTYP0, VMSEQ2 to VMSEQ0,
VMSIZE1, VMSIZE0, and DI31 to DI0 signals indicate the undefined state.
2.
n = 3 to 0
Figure 7-36 shows an example of the timing of a flyby single transfer (from external SRAM to external I/O
connected to the NT85E500). The settings of the registers in this figure are as follows.
[Register settings]
•
DBCn register = 0001H (2 transfers)
•
ASC register
Note
= FFEFH (CS2 address setting wait states = 2)
•
BCC register
Note
= FFEFH (CS2 idle states = 2)
•
DWC0 register
Note
= 7377H (CS2 wait states = 3)
Note
An NT85E500 register.