308
Table 8.6
Relationship between DMA Request Modes and Bus Modes
Address
Mode
Transfer Category
Request
Mode
Bus
Mode
Transfer
Size (Bits)
Usable
Channels
Single
External device with a DACK pin and
external memory
External
B/C
8/16
0, 1
External device with a DACK pin and
memory-mapped external device
External
B/C
8/16
0, 1
Dual
External memory and external memory
External/auto
B/C
8/16
0–3*6
External memory and memory-mapped
external device
External/auto
B/C
8/16
0–3*6
Memory-mapped external device and
memory-mapped external device
External/auto
B/C
8/16
0–3*6
External memory and on-chip memory
External/auto *1 B/C
8/16
0–3*6
External memory and on-chip peripheral
module
Any*2
B/C*4
8/16*5
0–3*6
Memory-mapped external device and
on-chip memory
External/auto *1 B/C
8/16
0–3*6
Memory-mapped external device and
on-chip peripheral module
Any*2
B/C*4
8/16*5
0–3*6
On-chip memory and on-chip memory
External/auto *3 B/C
8/16
0–3*6
On-chip memory and on-chip peripheral
module
Any*2
B/C*4
8/16*5
0–3*6
On-chip peripheral module and on-
chip peripheral module
Any*2
B/C*4
8/16*5
0–3*6
Notes: B: Burst mode, C: Cycle steal
1. For external requests, output DACK in the cycle in which the external memory or
memory-mapped external device is accessed.
2. External requests, auto requests and on-chip peripheral module requests are all
available. When the SCI or SIO is the transfer request source, however, the transfer
destination or transfer source must be the SCI or SIO, respectively. However, for
external requests, output DACK in the cycle in which the external memory or memory-
mapped external device is accessed.
3. For external requests in cycle-steal mode, DMA transfers between on-chip memories
are not possible. For DMA transfers between on-chip memories, use burst mode or
auto-request for the external request.
4. If the transfer request source is the SCI, SIO, cycle-steal mode only.
5. The access size permitted when the transfer destination or source is an on-chip
peripheral module register.
6. If the transfer request is an external request, channels 0 and 1 only.